Ecological Regionalization of Suitable Trees, Shrubs and Herbages for Vegetation Restoration in the Farming-Pastoral Zone of Northern China

To provide materials for the selection of plant species for vegetation restoration and reconstruction in the farming-pastoral zone in northern China, where the eco-environment has been already deteriorated by over-farming and over-grazing, the suitable trees, shrubs and herbages were examined, screened and identified under the guidance of four principles of taking precedence for ecological conservation, being beneficial to economic production, matching species (trees, shrubs and herbages) with the site, and giving consideration to the integrity of local administrative division. According to the key ecological factors that determine species growth and distribution in the zone, i.e., the lowest daily mean temperature in a year, annual accumulated temperature, and water regimes represented by the moist index, the ratio between annual rainfall and accumulated temperature (>0 degreesC), as well as the soil type influenced by climate, surface substances and landform, the farming-pastoral zone was regionalized into seven parts: ( I) Western Songliao Plain and Da Hinggan Mountain Region; (II) Upper Liaohe River Sandy Region; (III) Mid-Eastern Nei Mongol Plateau and Northwestern Heibei Mountain Region; (IV) Luliang, Taihang and Yanshan Mountain Region; ( V) Ordos Plateau Sandy Region; (VI) Northern Shaanxi to Eastern Gansu Loess Plateau Region; and (VII) Mid Gansu to Eastern Qinghai Plateau Loess Region. And the suitable trees, shrubs and herbages for each region were selected and tabularly introduced in detail.

Drought and flood characteristics in the farmingpastoral ecotone of northern China based on the Standardized Precipitation Index

The farming-pastoral ecotone of northern China(FPENC)provides an important ecological barrier which restrains the invasion of desert into Northwest China.Studying drought and flood characteristics in the FPENC can provide scientific support and practical basis for the protection of the FPENC.Based on monthly precipitation data from 115 meteorological stations,we determined the changes in climate and the temporal and spatial variations of drought and flood occurrence in the FPENC during 1960-2020 using the Standardized Precipitation Index(SPI),Morlet wavelet transform,and inverse distance weighted interpolation method.Annual precipitation in the FPENC showed a slightly increasing trend from 1960 to 2020,with an increasing rate of about 1.15 mm/a.The interannual SPI exhibited obvious fluctuations,showing an overall non-significant upward trend(increasing rate of 0.02/a).Therefore,the study area showed a wetting trend in recent years.Drought and flood disasters mainly occurred on an interannual change cycle of 2-6 and 9-17 a,respectively.In the future,a tendency towards drought can be expected in the FPENC.The temporal and spatial distribution of drought and flood differed in the northwestern,northern,and northeastern segments of the FPENC,and most of the drought and flood disasters occurred in local areas.Severe and extreme drought disasters were concentrated in the northwestern and northeastern segments,and severe and extreme flood disasters were mainly in the northeastern segment.Drought was most frequent in the northwestern segment,the central part of the northeastern segment,and the northern part of the northern segment.Flood was most frequent in the western part of the northwestern segment,the eastern part of the northeastern segment,and the eastern and western parts of the northern segment.The accurate evaluation of the degrees of drought and flood disasters in the FPENC will provide scientific basis for the regional climate study and critical information on which to base decisions regarding environmental protection and socio-economic development in this region.

Spatiotemporal variation of forest land and its driving factors in the agropastoral ecotone of northern China

As an important natural resource,forest land plays a key role in the maintenance of ecological security.However,variations of forest land in the agropastoral ecotone of northern China(AENC)have attracted little attention.Taking the AENC as an example and based on remote-sensing images from 2000,2010 to 2020,we explored the spatiotemporal variation of forest land and its driving factors using the land-use transfer matrix,spatial autocorrelation analysis and spatial error model.The results showed that from 2000 to 2020,the total area of forest land in the AENC increased from 75,547.52 to 77,359.96 km^(2) and the changes were dominated by the transformations among forest land,grassland and cropland,which occurred mainly in areas with the elevation of 500-2000 m and slope of 15°-25°.There was obvious spatial agglomeration of forest land in the AENC from 2000 to 2020,with hot spots of forest land gathered in the southern marginal areas of the Yanshan Mountains and the low mountainous and hilly areas of the Loess Plateau.The sub-hot spots around hot spots moved southward,the sub-cold spots spread to the surrounding areas and the cold spots disappeared.The spatiotemporal variation of forest land resulted from the interactions of natural environment,socioeconomic and policy factors from 2000 to 2020.The variables of average annual precipitation,slope,terrain relief,ecological conversion program and afforestation policy for barren mountains affected the spatial pattern of forest land positively,while those of annual average temperature,slope and road network density influenced it negatively.

Strategies for Prioritizing Ecological Construction with Consideration of Agricultural Industry Development in Northern China’s Agro- pastoral Ecotone : A Perspective of Opportunity Cost

In northern China’s agro-pastoral ecotone,there are conflicts between agricultural industry and ecological construction resource competition,and also problems urgently to be solved for economic growth and sustainable ecological improvement.Taking the development concept of"lucid waters and lush mountains being mountains of gold and silver"as the guiding principle of prioritizing ecological and green development,this paper studied the strategies for prioritizing ecological construction with consideration of economic development of agricultural industry from the perspective of opportunity cost.Through the analysis of opportunity cost,externality,and Pareto optimal theory,and using the calculation method of the unit equivalent factor value of terrestrial ecological service function,this paper calculated the ecological service value of forest,grassland,and farmland.It found that the ecological value of forest and grassland per unit area was greater than the ecological value of agricultural industry.This indicates that the opportunity cost of farmland for ecological construction was less than that of agricultural industry.Based on the theoretical and quantitative analysis,it came up with recommendations for establishing a comprehensive system for prioritizing ecological construction with consideration of agricultural industry development and establishing and improving the incentive mechanism of ecological construction.

Development of quantitative methods for detecting climate contributions to boundary shifts in farming-pastoral ecotone of northern China

The quantitative effect of climate change on fragile regions has been a hot topic in the field of responses to climate change. Previous studies have qualitatively documented the impacts of climate change on boundary shifts in the farming-pastoral ecotone （FPE）; however, the quantitative methods for detecting climate contributions remain relatively limited. Based on long-term data of meteorological stations and interpretations of land use since 1970, climate and land use boundaries of the 1970s, 1980s, 1990s and 2000s were delineated. To detect climate contributions to the FPE boundary shifts, we developed two quantitative methods to explore the spatial-temporal pattern of climate and land use boundary at the east-west （or south-north） （FishNet method） and transect directions （Digital Shoreline Analysis System, DSAS method）. The results indicated that significant differences were exhibited in climate boundaries, land use boundaries, as well as climate contributions in different regions during different periods. The northwest FPE had smaller variations, while the northeast FPE had greater shifts. In the northwest part of the southeast fringe of the Greater Hinggan Mountains and the Inner Mongolian Plateau, the shifts of climate boundaries were significantly related to the land use boundaries. The climate contributions at an east-west direction ranged from 10.7% to 44.4%, and those at a south-north direction varied from 4.7% to 55.9%. The majority of the results from the DSAS were consistent with those from the FishNet. The DSAS method is more accurate and suitable for precise detection at a small scale, whereas the FishNet method is simple to conduct statistical analysis rapidly and directly at a large scale. Our research will be helpful to adapt to climate change, to develop the productive potential, as well as to protect the environment of the FPE in northern China.

Adaptation to a Warming-Drying Trend Through Cropping System Adjustment over Three Decades:A Case Study in the Northern Agro-Pastural Ecotone of China

Long-term field monitoring data and historical crop data are useful to assess the impacts of climate change and to manage cropping systems. The objectives of this study are to understand the cropping system response to a warming-drying trend in the northern agro-pastural ecotone （NAE） of China and to document how farmers can adapt to the warming-drying trend by changing cropping system structure and adjusting planting date. The results indicate that a significant warming-drying trend existed in the NAE from 1980 to 2009, and this trend significantly decreased crop （spring wheat, naked oat, and potato） yields. Furthermore, the yield decreased by 16.2%-28.4% with a 1℃ increase in maximum temperature and decreased by 6.6%-11.8% with a 10% decrease in precipitation. Considering food security, water use efficiency, and water ecological adaptability in the semi-arid NAE, cropping system structure adjustment （e.g., a shift from wheat to potato as the predominant crop） and planting date adaptation （e.g., a delay in crop planting date） can offset the impact of the warming-drying trend in the NAE. Based on the successful offsetting of the impact of the warming-drying trend in the NAE, we conclude that farmers can reduce the negative effects of climate change and minimize the risk of crop failure by adapting their cropping system structure at the farming level.

Impacts of regional land-use patterns on ecosystem services in the typical agro-pastoral ecotone of northern China

A comprehensive understanding of the spatial-temporal evolution and driving forces on ecosystem services(ES)is essential for the agro-pastoral ecotone’s ecological security in northern China.However,the land-use pattern(LULC)agglomeration with spatial differentiation in the pastoral and agricultural areas has been rarely concerned.Taking distinct LULC(1980-2018)in Chifeng as an example,we compared four crucial categories of ESs with InVEST.Using SEM,we further contrasted the effects of several variables on regional ES variations in pastoral-dominated(North)and agriculture-dominated(South)regions,respectively.Results revealed the conversion between forest and grassland oriented the LULC transformation in the North.In contrast,human-activitiy-oriented land tended to occupy environmentally sensitive places in the South.Similar ES variations were supplied with the North outperforming the South when soil conservation was omitted.As for the impacts of regional ES variations,the natural and LULC policies both showed positive effects,whereas the anthropogenic factors showed positive in the North,which was negative in the South.Therefore,the ecologicallymaintained-dominant and ecologically-restored-dominant strategies should be separately adopted in the North and South.Our study provided appropriate regional ecological management suggestions for balancing the LULC-driven conflicts between ecological protection and regional development.

Land use pattern evolution and optimization in the Farming-Pastoral Zone of Northern China

Using information about the land cover of the Farming-Pastoral Zone of Northern China retrieved from multi-temporal NOAA/AVHRR and SPOT VEGETAN images obtained in 1989, 1994 and 1999, the authors analyzed land-use pattern evolution over this 10-year period and built a land-use pattern simulation model, based on which land-use pattern evolution and optimization modeling in this region were studied. Results showed that the proposed model can effectively simulate regional land-use patterns and help improve regional ecological environments.

中国北方农牧交错带的历史地理研究实践

北方农牧交错带课题的独特性与现代学术研究旨趣关系紧密,是区域民族史、环境史、全球变化等前沿问题的综合性学术田野。对北方农牧交错带历史现场进行重现,不仅是对特殊区域社会演进动态的历史关心,也是对区域生态治理与社会治理的现实关心,更是对我国东西部发展不平衡矛盾、国家生态安全及生态文明建设等重要议题的未来关心。自20世纪60年代以来,历史地理学研究者参与到北方农牧交错带相关问题的研究中,充分发挥学科优势,运用文献记载、考古成果等代用证据,深入实践区域历史地理学理论和方法,对区域典型地区历史自然地理、历史城市地理、区域人地互动等专题进行了深入地探讨。历史地理学对北方农牧交错带研究的贡献主要表现在对农牧交错带概念不断深入挖掘与拓宽、推动区域研究时空范围的延展、弥补区域研究方法的不足等多方面。而得益于北方农牧交错带历史地理课题的丰富性、多样性和特殊性,历史地理学学科思想、研究理论、研究方法和手段也得到了长足的实践与发展。

北方农牧交错区不同播期和刈割期对燕麦饲草产量和品质的影响

为明确不同播期和刈割期对燕麦(Avena sativa L.)饲草产量和品质的影响,本研究以粮饲兼用燕麦品种‘白燕2号’为材料,于2018—2019年在内蒙古农牧交错区进行了5个播期和3个刈割期的田间试验。结果表明:推迟播种可获得相对较高的燕麦饲草产量和品质,但推迟播种提高了中性洗涤纤维和酸性洗涤纤维含量,其中酸性洗涤纤维含量受年份和刈割期影响较大;燕麦饲草粗蛋白含量受刈割时间影响显著(P<0.001),在抽穗期含量最高;燕麦饲草产量在灌浆期达到最大;生育期间积温对燕麦饲草生长影响显著,拔节到抽穗期的积温增加不利于燕麦饲草产量和品质的形成,但出苗到分蘖间的积温增加可提高粗脂肪和酸性洗涤纤维的含量。总之,在北方农牧交错区种植燕麦饲草‘白燕2号’,在5月中下旬之间播种,在灌浆期刈割,可获得相对优质高产的燕麦饲草。

北方草地及农牧交错区草地植被碳储量及其影响因素

【目的】草地生态系统在全球碳平衡中有重要的意义,草地植被碳库及其变化机制研究是植被生态学的重要命题。本文研究北方草地和农牧交错区草地植被碳密度及其空间格局,解析不同区域草地植被碳密度的关键影响因素,分析了气候、土壤、放牧等因素对地上地下植被碳库的相对贡献。【方法】基于2002—2009年北方草地及农牧交错带草地植被调查数据,结合同期MODIS/NDVI遥感影像和1﹕100万草地类型图,建立了我国主要草地类型的生物量估算模型;整合野外考察数据和前人研究结果,探讨了研究区地上地下生物碳库及其空间格局;基于研究区255个县级行政单元,分析了不同类型草地植被碳库与气候要素、土壤要素及家畜承载量的关系,应用一般线性模型(GLM)解析了不同影响因素对草地碳密度的相对贡献。【结果】(1)北方草地与农牧交错区草地地上平均生物碳密度为36.9 g C·m^-2,地下生物碳密度为362.9 g C·m^-2,地下生物碳密度高于地上10倍,均呈从东到西递减的趋势,频率分布图基本服从对数正态分布,不同草地类型的生物碳密度存在明显差异;(2)整个研究区及草原亚区、荒漠亚区、农牧交错亚区内,地上生物量与年降水量(MAP)呈极显著正相关、与年均气温(MAT)均呈极显著负相关,与土壤黏粒含量(Clay%)呈显著正相关、与土壤砂粒含量(Sand%)呈显著负相关,整个研究区家畜承载量与草地地上生物量之间呈极显著正相关;(3)一般线性模型(GLM)分析结果表明,年平均降水量(MAP)、年均气温(MAT)、土壤黏粒含量(Clay%)、放牧强度对地上生物量空间变异的解释率分别达到29.6%(P<0.001)、5.8%(P<0.001)、0.8%(P<0.05)、1.3%(P<0.001);地下生物量的空间变异主要来自于年降水量(MAP)、年均气温(MAT)、土壤砂粒含量(Sand%),对方差的解释率分别达到12.1%(P<0.001)、6.8%(P<0.001)、1.9%(P<0.005),放牧强度没有明显贡献。【结论】气候条件尤其是年降水量是草地生物量碳库的主要影响因素,但对地上生物量影响更为明显;土壤质地对植被生物碳库也有显著贡献,尤其对地下生物量的影响更加显著;放牧强度只能解释地上生物量变化的1.3%、对地下生物量没有显著贡献,这一发现意味着气候对生物量碳库的贡献远大于放牧影响。

北方农牧交错带参考作物蒸散量时空变化与成因分析

利用北方农牧交错带46个气象站1961-2013年气象资料,采用Penman-Monteith公式法计算该地区参考作物蒸散量(ET_0)、ET_0对气象因子的敏感性系数、气象因子对ET_0的贡献率,并通过趋势分析、GIS空间插值方法对这些指标的时空变化进行分析。结果表明:(1)北方农牧交错带年ET_0平均值在839~1097mm,近53a来以0.21mm·a^(-1)的速率减小。(2)空间分布上,ET_0总体呈现"一高二低"的分布格局:陕北高原为高值区,大兴安岭北部高纬地区、青东农区及陇中片区为两大低值中心区。且陕北高原、陇中及青东农区61%的站点ET_0平均以0.85mm·a^(-1)(P<0.05)的趋势递增,而吉林西部、科尔沁沙地、辽西地区则呈明显减小趋势。(3)气象因子对ET_0的贡献受ET_0对气象因子的敏感性和气象因子的相对变化共同影响,其中北方农牧交错带ET_0对相对湿度最敏感,其次为平均风速;但近53a来风速呈极显著下降趋势,下降速率达0.0154m·s^(-1)·a^(-1)(P<0.001),因此,综合分析结果表现为风速对ET_0的贡献量最大,说明北方农牧交错带ET_0下降主要归因于风速的降低。

北方农牧交错带农田水分生产潜力开发研究进展与思考

不合理的土地利用方式与利用强度导致农业用水不合理是造成北方农牧交错带生态退化的重要原因,适度开发利用农田水分是当前发展农业生产和重建生态系统的关键。分析了农田水分研究进展、农田水分生产潜力研究进展及当前农田水分生产潜力开发面临的新形势与新任务,提出要遵循适度原则合理开发利用北方农牧交错带农田水分生产潜力。初步辨识了农田水分生产潜力适度开发的基本内涵,提出了北方农牧交错带农田水分生产潜力适度开发的研究框架与关键科学命题。当前,要遵循农田水分适度开发的思想指导当地农业生产,恢复生态,促进北方农牧交错带的可持续发展。

北方农牧交错带农田生态系统健康评价——以武川县为例

采用生态系统健康的理论和评价方法分析评价农田生态环境问题具有重要的理论和现实意义,应用生态健康指数定量评价农田健康水平是生态系统管理的重要内容。以武川县农田为研究对象,选择水分、生物量、幅宽等代表性指标,分析了不同作物覆盖下农田生态健康指数。结果表明:不同种植模式间农田健康指数差别明显。播种期较早的小麦田最为健康,没有采用地膜覆盖的马铃薯田健康指数最低,而采用地膜覆盖的马铃薯田健康指数比较高。推广小麦栽培和覆膜栽培是北方农牧交错带农田很好的经营管理模式,具有推广价值,是缓解该地区环境的有效手段之一。

气候和土地利用变化对中国北方农牧交错带植被覆盖变化的影响

基于1986、2000年中国北方农牧交错带的遥感影像及研究区的气象数据,利用植被覆盖度信息提取模型研究了1986—2000年间研究区植被覆盖度的时空变化,并分析了气候和土地利用变化对植被覆盖度变化的影响.结果表明:1986—2000年,研究区高盖度植被的面积缩减,低盖度植被的面积增加;植被覆盖升高区主要位于该区东北段的东部、北段的西部和西北段的西部,其他地段的植被覆盖明显退化;植被覆盖度与降水、干燥度指数呈正相关,与温度呈负相关;不同土地利用类型的植被覆盖度变化方向和程度各异.

北方农牧交错带生态系统服务价值测算及变化

基于1986年和2000年北方农牧交错带生态系统类型、NPP和植被覆盖度的分布,利用遥感和GIS技术,结合生态经济学方法,测算了北方农牧交错带生态系统服务功能的经济价值及动态变化。结果表明:(1)在生态系统服务价值的构成中,草地、农田和森林的贡献率最大;(2)从单位面积价值看,森林和灌丛服务功能的单位面积价值最高;(3)在水平分布上,生态系统服务价值的区域差异明显,其分布受气候和人类活动影响较大;在垂直分布上,地形因子对生态系统服务价值的影响较大,人类活动影响微弱;(4)1986～2000年间,各个生态系统服务功能的价值及其总价值都在下降,单位面积价值的最大值由东北向西南方向移动到交错带的中部。

北方农牧交错带界线变迁区的土地利用与景观格局变化

交错带是相邻生态系统的边缘交汇带,是陆地生态系统对全球变化和人为干扰响应较为敏感的地段。在全球气候变化和人为干扰的影响下,北方农牧交错带的地理位置和界线不断变迁,界线变迁区的土地利用和景观格局也处于快速的变化之中。该文基于气象和土地利用数据,利用遥感、GIS技术和景观生态学方法,界定了北方农牧交错带及界线变迁区的地理位置,并分析了1986-2000年界线变迁区的土地利用和景观格局时空变化特征。结果显示:(1)北方农牧交错带的西北界、东南界缓冲区土地利用结构变化、不同地类之间的相互转化及土地利用动态度变化存在明显区域差异;(2)西北界、东南界缓冲区景观重心迁移的距离和方向、景观格局变化呈现出不同的特征。

北方农牧交错带气候变化与旱涝响应特征

依据北方农牧交错带1961—2012年46个气象站气温、降水数据,采用气候倾向率、Mann—Kendall检测及Kring插值法,对该区气候变化及旱涝时空特征进行了分析。结果表明:(1)近52a,北方农牧交错带气候呈现暖干化趋势,1986年后暖干化趋势有所加强。(2)不同区域不同时段,气温、降水表现出不同的变化特征。(3)全区及3个子区旱涝等级均呈上升趋势,不同区域旱涝等级变化趋势差异显著。(4)北方农牧交错带大涝呈"片状"分布,大旱呈"斑点状"分布。全区整体相对较易发生大旱,东北段相对更易发生大涝,华北段更易发生大旱。

基于土地利用和气候变化的北方农牧交错带界线变迁

基于1961～2005年中国北方9省、自治区的218个气象站点的气象资料及1986年和2000年的土地利用数据,从全球气候变化和土地利用变化角度分别界定了北方农牧交错带的地理位置,并分析了其界线变迁特征.结果表明,北方农牧交错带的地理位置还存在一定争议.交错带整体上已向西北移动.西北界已向北深入到纯牧区,东南界附近也由农牧交错区转成纯农区.气候界线向东南变迁,土地利用界线向西北变迁,两者变迁方向相反.东北段和华北段的界线变迁幅度远大于西北段.

北方农牧交错带草木犀属外来植物沿公路分布和扩展的影响因素探讨

公路的建设给原有的生态系统带来人为于扰和影响,公路建筑材料的运输给外来植物的引入带来风险,公路修建以及环境因子则影响外来物种的建植和扩繁。选择北方农牧交错带典型的柏油公路,对草木犀属(Melilotus)外来植物沿公路的入侵状况进行样带调查,以探讨外来植物沿公路分布和扩散的影响因素。结果表明:公路两侧的土地利用方式是影响草木犀属植物分布的主要因素,路旁有农田的地段中,草木犀属植物的分布密度要显著大于有草地的地段(P<0.05)。距离则是影响草木犀属植物分布密度的重要因素,随着从路基到路旁生境距离的增加,草木犀属的分布密度呈显著下降趋势(P<0.05)。此外,公路的走向也影响草木犀属植物的分布,草木犀属在下风向的分布密度显著大于上风向的分布密度(P<0.05);公路两旁高大树木的遮阴同样影响草木犀属植物沿公路的分布,遮阴环境影响草木犀属一年生植物的密度(P<0.05),但对于二年生植株没有显著影响。