Whether human-induced activities could change the gradient pattern of coastal land use along the sea-land direction:a case study in Manila Bay,Philippines

Increasing intense human activities have largely changed the coastal landscape and caused many environmental issues.However,whether human-induced activities could change the coastal land use gradient pattern,an important coastal zonal characteristic along the sea-land direction,remains unclear.Manila Bay was selected as the study area in this work.According to the distance of the land use and land cover(LULC)to the coastline,we clustered the typical coastal land use sequence patterns(CLUSPs)along the sea-land direction between 1988 and 2016 in Manila Bay and found the following.(1)Four typical CLUSPs,including the natural CLUSP dominated by forest land and grassland,the agricultural CLUSP dominated by dry farm and paddy field,the urbanised CLUSP dominated by construction land and the fishery CLUSP dominated by fishing farm,were mined in 1988.Three typical CLUSPs(a natural CLUSP,an intermediate CLUSP between the agricultural and urbanised CLUSPs,and a fishery CLUSP)were mined in 2016.(2)Affected by the dominant LULC,these typical CLUSPs showed a regular spatial pattern along the sea-land direction.For example,the typical natural CLUSP showed a landward pattern due to the long distance between the forest land and grassland and the coastline.(3)However,influenced by urban and aquaculture expansion,the land intensification of the CLUSP exhibited an obvious increase and caused the decrease of the CLUSP diversity from 1988 to 2016.The increase in the area of LULC coverage showed no obvious correlation with its distance from the coastline(DFC),but the net increase rate of LULC coverage had a significant negative correlation with the DFC.Therefore,human-induced activities have a large impact on the gradient pattern of coastal land use along the sea-land direction.

Characteristics and drivers of the soil multifunctionality under different land use and land cover types in the drylands of China

The drylands of China cover approximately 6.6×106 km2 and are home to approximately 5.8×10^(8)people,providing important ecosystem services for human survival and development.However,dryland ecosystems are extremely fragile and sensitive to external environmental changes.Land use and land cover(LULC)changes significantly impact soil structure and function,thus affecting the soil multifunctionality(SMF).However,the effect of LULC changes on the SMF in the drylands of China has rarely been reported.In this study,we investigated the characteristics of the SMF changes based on soil data in the 1980s from the National Tibetan Plateau Data Center.We explored the drivers of the SMF changes under different LULC types(including forest,grassland,shrubland,and desert)and used structural equation modeling to explore the main driver of the SMF changes.The results showed that the SMF under the four LULC types decreased in the following descending order:forest,grassland,shrubland,and desert.The main driver of the SMF changes under different LULC types was mean annual temperature(MAT).In addition to MAT,pH in forest,soil moisture(SM)and soil biodiversity index in grassland,SM in shrubland,and aridity index in desert are crucial factors for the SMF changes.Therefore,the SMF in the drylands of China is regulated mainly by MAT and pH,and comprehensive assessments of the SMF in drylands need to be performed regarding LULC changes.The results are beneficial for evaluating the SMF among different LULC types and predicting the SMF under global climate change.

Quantitative Assessment of Impacts of Regional Climate and Human Activities on Saline-alkali Land Changes:A Case Study of Qian'an County,Jilin Province

Interdecadal and interannuat variations of saline-alkali land area in Qian＇an County, Jilin Province, China were comprehensively analyzed in this paper by means of satellite remote sensing interpretation, field flux observations and regional climate diagnosis. The results show that on the interannual scale, the impact of climate factors accounts for 71.6% of the total variation of the saline-alkali land area, and that of human activities accounts for 28.4%. Therefore the impact of climate factors is obviously greater than that of human activities. On the interdecadal scale, the impact of climate factors on the increase of the saline-alkali land area accounts for 43.2%, and that of human activities accounts for 56.8%. The impact of human activities on the variation of saline-alkali land area is very clear on the interdecadal scale, and the negative impact of human activities on the environment should not be negligible. Besides, changes in the area of heavy saline-alkali land have some indication for development of saline-alkali land in Qian＇an County.

Simulation and Analysis of Land System Structure Changes in Huang-Huai-Hai Plain Area

The dynamic changes of land system in Huang - Huai - Hai Plain between 1988 and 2000 were researched in this paper. Spatial dominance econometric model was estabilished on 1 km cell to quantificafionally analyze the driving-force for the dynamic change mechanism of land system, such as natural, social and economic factors. The future dynamic changes of land system in Huang - Huai - Hai Plain on each 1 km cell during 2000 to 2020 were stimulated by combining the dynamic changes of land system on each 1 km cell with different situations. The research indicated that the dynamic changes of land system structure changed mainly from the cultivated areas to building areas and industrial areas, and forest areas increased during this period. Although the revolutions of land system structure were different during 2000 to 2020 with the different referrence standard, ecological protection and economic development, the primary dynamic changes of land system structure were that the increase of building land areas with the decline cuhivaled land areas and the increase of woodlands.

HUMAN DRIVING MECHANISM OF REGIONAL LAND USE CHANGE:A CASE STUDY OF KARST MOUNTAIN AREAS OF SOUTHWESTERN CHINA

Based on analysis of the change of land use and related social- economic factors in karst mountain areas of southwestern China, the index system characterizing land use change and its human driving forces in county scale is put forward. Then the relationship of land use change and the driving forces is studied by statistic analysis to identify quantitatively the contribution of human forces and their differences in driving land use change. Moreover, taking the Luodian County as the case, a model simulating the annual change of cultivated land area under the driving of human forces is built. Result of the study will supply reference for the management of the relationship of man and land in karst mountain areas of southern- western China, and accumulate research experience for further study on land use/cover change.

Economic Structure Transformation and Land Use Change of the Changjiang River Basin

Land, as a key factor of production, is an appropriate indicator of national and regional economic structure transformation. Land use in the Changjiang （Yangtze） River Basin （CRB） since the 1950s has experienced these changes. Industrialization has been the most powerful force of the change in the regional development of the CRB. Virtually all regional resources were put into this effort to modernize the industrial production and urban construction systems of the CRB whose industrialization and urbanization has been a success story, with impressive structural change in both production and land use. These changes are evident ih modem urban areas, but even more in traditionally rural areas. The regression analysis of regional development in the CRB over an extended period shows that the dominant factor in regional land use change is widespread industrialization in rural areas rather than the expansion of urban area. Thus, urbanization has had a limited influence on land use change in the CRB. A major task in realizing more sustainable land use in the future development of CRB is to relocate industrial activities from rural to urban areas.

Response of ecosystem service value to land use/cover change in the northern slope economic belt of the Tianshan Mountains, Xinjiang, China

Land use/cover change(LUCC)is becoming more and more frequent and extensive as a result of human activities,and is expected to have a major impact on human welfare by altering ecosystem service value(ESV).In this study,we utilized remote sensing images and statistical data to explore the spatial-temporal changes of land use/cover types and ESV in the northern slope economic belt of the Tianshan Mountains in Xinjiang Uygur Autonomous Region,China from 1975 to 2018.During the study period,LUCC in the study region varied significantly.Except grassland and unused land,all the other land use/cover types(cultivated land,forestland,waterbody,and construction land)increased in areas.From 1975 to 2018,the spatial-temporal variations in ESV were also pronounced.The total ESV decreased by 4.00×10^(8) CNY,which was primarily due to the reductions in the areas of grassland and unused land.Waterbody had a much higher ESV than the other land use/cover types.Ultimately,understanding the impact of LUCC on ESV and the interactions among ESV of different land use/cover types will help improve existing land use policies and provide scientific basis for developing new conservation strategies for ecologically fragile areas.

Regional Variability of the Effects of Land Use Systems on Soil Properties

In order to explore the regional variability of the effects of land use systems on soil properties, Shouyang County in Shanxi Province and Danling County in Sichuan Province of China were selected as the study areas. Field soil samples of the four land use systems （natural forest, forest plantation, shrubland, and cropland） were collected, respectively, from the two areas. The general statistical tools were used to analyze soil data. The results showed that the influence of land use systems on soil properties was significant. In general, soils in slightly human-disturbed land use systems presented a higher fertility level than those in strongly human-disturbed land use systems in both areas. Furthermore, the impacts of the same land use systems on soil properties showed a distinct regional variability, and even in the same land use system, different farming systems and site management measures （such as irrigation, fertilization, and pesticides） could also lead to the regional heterogeneity in soil properties. The regional variability of land use effects on soil properties reveals the regional variability of the effects of human activities on environmental changes, and could explain the complex relationship between humans and the natural environment in certain ways.

Spatial pattern of land cover change in China's semiarid environment

This study seeks a routine to quantify spatial pattern of land cover changes in semiarid environment of China based on post-classification comparison method. The method consists of three major steps: (1) the image classification and unification of classified results based on two-level land cover classification themes, (2) the establishment of land cover change classes based on an unification land cover classification theme, (3) the reclassification and mapping of land cover change classes with three overall classes including no-change, gain and loss based on the unification land cover class. This method was applied to detect the spatial pattern of land cover changes in Yinchuan Plain, one of famous irrigation agricultural zones of the Yellow River, China. The results showed the land cover had undergone a remarkable change from 1991 to 2002 in the study area (the changed area was over 30%). Rapid increase of cropland (12.5%), built-up area (131.4%) and rapid decrease of bare ground (51.7%) were alarming. The spatial pattern of land cover changes showed clear regional difference in the study area and was clearly related to human activities or natural factors. Thus, it obtained a better understanding of the human impact on the fragile ecosystem of China’s semiarid environment.

How precipitation and grazing influence the ecological functions of drought-prone grasslands on the northern slopes of the Tianshan Mountains, China?

Drought-prone grasslands provide a critical resource for the millions of people who are dependent on livestock for food security.However,this ecosystem is potentially vulnerable to climate change(e.g.,precipitation)and human activity(e.g.,grazing).Despite this,the influences of precipitation and grazing on ecological functions of drought-prone grasslands in the Tianshan Mountains remain relatively unexplored.Therefore,we conducted a systematic field investigation and a clipping experiment(simulating different intensities of grazing)in a drought-prone grassland on the northern slopes of the Tianshan Mountains in China to examine the influences of precipitation and grazing on aboveground biomass(AGB),soil volumetric water content(SVWC),and precipitation use efficiency(PUE)during the period of 2014–2017.We obtained the meteorological and SVWC data using an HL20 Bowen ratio system and a PR2 soil profile hydrometer,respectively.We found that AGB was clearly affected by both the amount and seasonal pattern of precipitation,and that PUE may be relatively low in years with either low or excessive precipitation.The PUE values were generally higher in the rapid growing season(April–July)than in the entire growing season(April–October).Overall,moderate grazing can promote plant growth under water stress conditions.The SVWC value was higher in the clipped plots than in the unclipped plots in the rapid growing season(April–July),but it was lower in the clipped plots than in the unclipped plots in the slow growing season(August–October).Our findings can enhance the understanding of the ecological effects of precipitation and grazing in drought-prone grasslands and provide data that will support the effective local grassland management.

Linking soil organic carbon mineralization to soil physicochemical properties and bacterial alpha diversity at different depths following land use changes

Background Anthropogenic land use changes(LUCs)impart intensifying impacts on soil organic carbon(SOC)turnover,leading to uncertainty concerning SOC mineralization patterns and determining whether soils act as“source”or“sink”in the global carbon budget.Therefore,understanding the SOC mineralization characteristics of different LUC patterns and their potential influencing factors is crucial.An indoor incubation experiment was conducted to study the SOC mineralization patterns and their relevance to soil physicochemical properties,soil enzyme activity,SOC fractions,and bacterial alpha diversity.The soils were collected from two layers of five typical LUC patterns in Yellow Sea Forest Park,including four that were converted from wheat-corn rotation systems[a gingko plantation(G),a metasequoia plantation(M),a gingko-wheat-corn agroforestry system(GW),and a gingko-metasequoia system(GM)]and a traditional wheat-corn system(W).Results LUCs had significant and diverse impacts on the SOC content and SOC fraction contents and on soil enzyme activity.The cumulative SOC mineralization was significantly higher in the M systen than in the W and GW systems at 0-20 cm depth and higher in the G system than in the GW system at 20-40 cm depth after 60-day incubation.The mineralization ratio was highest in the W system and lowest in the GW system.The soil pH and bulk density had a significant negative correlation with the cumulative SOC mineralization,while the soil bacterial Shannon index had a significant positive correlation with cumulative SOC mineralization.Multiple stepwise linear regression analysis showed that the SOC mineralization potential was dominantly explained by the bacterial Shannon index and operational taxonomic units(OTUs).The GW system had lower potentially mineralizable SOC and higher SOC stability.Additionally,the incubation time and cumulative SOC mineralization were well fitted by the first-order kinetic equation.Conclusions LUCs significantly changed SOC mineralization characteristics and the results highlighted the important roles of the bacterial community in soil carbon cycling,which contributes to the fundamental understanding of SOC turnover regulation.

塔里木河流域土地利用及人类活动强度的时空演化特征研究

[研究目的]人类活动引起的土地利用/覆被变化是全球环境变化的重要组成部分,旱区土地利用对区域水文和生态的影响尤为显著,探究土地利用变化及其对人类活动的响应对西北干旱内陆生态与资源环境可持续发展具有重要意义。[研究方法]基于1980-2018年间共5期遥感影像,结合土地利用动态度、土地利用转移矩阵和人类活动强度指数分析塔里木河流域各水资源分区土地利用变化特征。[研究结果]近40年中,塔里木河流域耕地、建设用地和林地面积分别增加1.58×10^(4)km^(2)、1.2×10^(3) km^(2)和347 km^(2),而草地、未利用地和水域面积分别减少1.33×10^(4)km^(2)、0.32×10^(4)km^(2)和815 km^(2)。各水资源分区中塔里木河干流土地利用类型变化最大,其次为渭干河、阿克苏河和喀什噶尔河流域。自2000年以来,塔里木河流域建设用地当量面积和人类活动强度增加相对较快,特别是2000-2010年间呈显著增长趋势。[结论]塔里木河流域各水资源分区的人类活动强度呈显著的空间差异性。社会经济发展和政策的导向性作用是塔里木河流域土地利用变化和人类活动强度的主要影响因素。

青藏高原土地利用变化对人类活动的响应

土地利用是反映人类活动的重要因素,对青藏高原的土地利用识别和时空演变进行分析是我国生态环境脆弱地区可持续发展规划的重要手段.以2001年、2010年与2020年3期500 m分辨率的土地利用数据为基础,探讨21世纪以来人类活动作用下青藏高原的土地利用时空演变规律.结果表明:1)牧草地与未利用地是青藏高原主要的土地利用类型,2001年以来,除建设用地面积变化平稳,耕地与未利用地面积减少外,其余3类均呈现不同程度的扩张.2)从变化速度看,青藏高原范围内的甘肃土地利用变化速度减慢,青海、四川反之,其余3个地区变化稳定;耕地与未利用地的面积缩减速度变缓,水域面积则不断扩大.3)2个时段的土地利用转移表现为以未利用地与牧草地的相互转化为主,其次为水域与未利用地、林地与牧草地的相互转化特征.4)人类活动对青藏高原的土地利用影响程度略有增大,影响范围涉及6个省(自治区),其中人类活动作用下牧草地的扩张程度最大.该结果不仅能为青藏高原的土地资源规划和生态功能保护提供科学参考,而且可为构建和谐的人地关系发挥重要作用.

An equilibrium analysis of the land use structure in the Yunnan Province, China

Global land use structure is changing rapidly due to unceasing population growth and accelerated urbanization, which leads to fierce competition between the rigid demand for built-up area and the protection of cultivated land, forest, and grassland. It has been a great challenge to realize the sustainable development of land resources. Based on a computable general equilibrium model of land use change with a social accounting matrix dataset, this study implemented an equilibrium analysis of the land use structure in the Yunnan Province during the period of 2008-2020 under three scenarios, the baseline scenario, low TFP （total factor productivity） scenario, and high TFP scenario. The results indicated that under all three scenarios, area of cultivated land declined signifi- cantly along with a remarkable expansion of built-up area, while areas of forest, grassland, and unused land increased slightly. The growth rate of TFP had first negative and then positive effects on the expansion of built-up area and decline of cultivated land as it increased. Moreover, the simulated changes of both cultivated land and built-up area were the biggest under the low TFP scenario, and far exceeded the limit in the Overall Plan for Land Utilization in the Yunnan Province in 2020. The scenario-based simulation results are of important reference value for policy-makers in making land use decisions, balancing the fierce competition between the protection of cultivated land and the increasing demand for built-up area, and guaranteeing food security, ecological security, and the sustainable development of land resources.

Human and climatic drivers of land and water use from 1997 to 2019 in Tarim River basin,China

Climate and human activities change spatial and temporal distribution of water and land use.The Tarim River,the largest inland river in China,faced a long-term exploitation of land and water over a rapid economic development.We analyzed land and water use from 1997 to 2019 in Tarim River Basin by Landsat images,and data on hydrology,climate,population,economy and PM_(2.5)(air particulate matter≤2.5μm).Agricultural land expanded the fastest(4-11%),followed by natural vegetation(15-16%)and water area(4-5%)with population and economic increase.Air quality(PM_(2.5)μg m^(−3))improved in upper(62-27)and middle(48-17)reaches.The water area in lower increase 5%because of ecological water delivery since 2000.Land use in the lower reach was dominated by agriculture,where the downstream runoff consumption increased by 6.8 times.The average annual air temperature and precipitation gradually increased by 0.5℃and 51 mm in source and 0.9℃and 30 mm in main reaches.The average annual water consumption in upper and middle reaches was 4×10^(9)m^(3),accounting for 87%of input runoff in the main reach.Water consumption in middle reach increased by 33 times in 2009-2017.The industry structure was changing from primary to secondary and tertiary industry.To sum up,implementation of water saving strategies and ecological water delivery restored local ecology.Sustainable strategies should be applied facing industrialization.Furthermore,changing the industry structure and restoring the degraded farmlands to grasslands or forests would keep sustainability of Tarim River Basin.

Profoundly entwined ecosystem services,land-use change and human well-being into sustainability management in Yushu,Qinghai-Tibet Plateau

The nexus exploration among land use/land cover change,ecosystem services and human well-being has been increasingly crucial in the context of Future Earth.However,the spatial heterogeneity and the entwining process among these three aspects have not yet been in-depth and systematically explored.Here we identified the spatiotemporal pattern of ecosystem services during the past 20 years in Yushu,the eco-fragile region and the centre of Qinghai-Tibet Plateau,as well as clarified its relationships with land use change and human well-being.We revealed that:(1)The structure of the ecosystem and land use in this area have been increasingly stable,and the ecological projects have exerted a positive impact.(2)Although the ecological environmental issues still need more attention,the ecosystem services of the area have been positively developing.(3)Derived by the ecosystem services increase,environmental projects and policies,the human well-beings of culture and education performed much better than other aspects.(4)It is crucial to carry out long-term ecological projects and increase educational investment for maintaining the stability of this ecologically fragile area.This study provides significant support for the regional ecological sustainability decision making,especially for the Qinghai-Tibet Plateau,the roof of the world.

Runoff Change of Naoli River in Northeast China in 1955–2009 and Its Influencing Factors

Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 for Bao′an station, from 1955 to 2009 for Baoqing station, from 1956 to 2009 for Caizuizi station and from 1978 to 2009 for Hongqiling station. The influences of climate change and human activities on runoff change were investigated, and the causes of hydrological regime change were revealed. The seasonal runoff distribution of the Naoli River was extremely uneven, and the annual change was great. Overall, the annual runoff showed a significant decreasing trend. The annual runoff of Bao′an, Baoqing, and Caizuizi stations in 2009 decreased by 64.1%, 76.3%, and 84.3%, respectively, compared with their beginning data recorded. The wet and dry years of the Naoli River have changed in the study period. The frequency of wet year occurrence decreased and lasted longer, whereas that of dry year occurrence increased. The frequency of dry year occurrence increased from 25.0%-27.8% to 83.9%-87.5%. The years before the 1970s were mostly wet, whereas those after the 1970s were mostly dry. Precipitation reduction and land use changes contributed to the decrease in annual runoff. Rising temperature and water project construction have also contributed important effects on the runoff change of the Naoli River.

变化环境下子牙河流域水文过程影响要素分析

构建添加水库及取用水模块的SWAT模型,在考虑人类活动影响的基础上,分析土地利用类型及气候变化对子牙河流域水文要素的影响,并利用统合还原法计算人类活动及气候变化对研究区的径流变化的贡献率。结果表明:1980-2020年草地、耕地及水域面积呈减少趋势,建设用地呈增加趋势,其他土地利用类型变化趋势不明显;土地利用类型变化使得流域地表产流增加3.5 mm,地下水补给和蒸散发分别减少0.15 mm和2.93 mm;1980-2020年研究区年降水量呈不显著上升趋势,年气温呈显著上升趋势,气候变化使得流域地表产流、地下水补给及蒸散发有不同程度的增加;人类活动和气候变化对流域径流减少的贡献率分别为66.36%和33.64%,人类活动占据相对主导的地位。

基于土地利用模拟预测模型分析的城市绿色空间发展多情景模拟及建设时序研究——以湛江市中心城区为例

城市绿色空间是未来中国城镇战略发展的重要生态空间载体。城市中心城区的绿色空间生态系统服务价值可作为未来城市生态空间规划的重要依据。生态服务系统之间的权衡或协同关系可通过不同土地利用方式和利用强度表征显现。通过对湛江市中心城区绿色空间应用土地利用模拟预测(PLUS)模型进行自然发展情景与国土空间规划情景双情景下2035年土地利用变化模拟,采用当量因子法及热点分析对生态系统服务价值及其高低值在空间上的聚集程度进行分析,与人类活动强度空间分布进行叠置,得出国土空间规划政策下湛江市中心城区城市绿色空间发展优先级分区,优先化解建设用地与绿色空间发展矛盾,为规划政策提供空间政策的量化数据基础,为其可行性实施、时序安排及预期结果提供数据支撑与建议。结果表明:(1)规划政策情景与自然发展情景未来土地利用模拟结果相比,耕地、林地增多,整体水域得到有效保护,建设用地蔓延受到抑制。(2)生态系统服务价值在2035年规划政策情景>2020年实际情景>2035年自然发展情景,分别约为12.22亿元、11.89亿元、10.53亿元,规划政策情境下生态系统服务价值总量较自然发展情景下提升约1.69亿元,生态环境效益得到显著提升,调节服务、支持服务、供给服务、文化服务分别提升约1.38、0.13、0.12、0.06亿元,但文化服务与2020年现状相比降低约0.31亿元,在未来建设过程中切勿忽视景观美学的营造。(3)通过生态系统服务及人类活动强度的空间分布分析对绿色空间发展进行优先级分区,建议以赤坎区中部、沿海域建设用地及水域范围、其他区域顺序进行分区建设。

1985—2015年洛川塬土地利用/覆被变化及人类活动影响——以陕西省洛川县为例

洛川塬是黄土高原第二大黄土塬面,也是黄土高原面积最大的苹果种植区。近几十年来,由于塬面高强度人类活动影响,洛川塬沟道侵蚀剧烈,塬面萎缩呈现逐年加剧的趋势,严重影响了塬区的生产、生活和生态安全。因此,清晰了解近几十年来洛川塬土地利用/覆被变化及人类活动影响,对于洛川塬的保护和水土流失治理至关重要。本文使用遥感、地理信息系统和数学方法,以洛川塬主体洛川县为例,对洛川县1985年、2000年和2015年的土地利用数据进行了解译,分别从土地利用变化速度、转移方向和土地利用程度三方面综合分析了洛川县近30 a土地利用时空变化的规律及人类活动影响。研究结果表明:(1)1985—2015年洛川县主要的土地利用类型为林地、草地和耕地,三者面积占比达91.29%;近30 a土地利用变化最大的特点为建设用地面积持续增加且增幅最大,共增加了117.16 km^(2),年均增加5.11%,其中1985—2000年建设用地面积增加了38.13 km^(2),2000—2015年增加了79.03 km^(2),建设用地面积的增加主要由耕地转入;(2)近30 a人类活动对洛川县土地利用变化的影响主要体现在林地、草地、耕地、建设用地之间的转换;前15 a(1985—2000年)林草地面积减少,耕地和建设用地面积增加;后15 a(2001—2015年)林草地和建设用地面积增加,耕地面积减少;(3)近30 a洛川县的综合土地利用动态度呈现增加趋势但增幅较小,前15 a(1985—2000年)综合土地利用动态指数小于后15 a(2001—2015年),表明后期人类活动对土地利用综合开发利用起到积极的影响。