The Ecological Effects of Young Elm Trees Belt-Pumpkin Strip Intercropping System at the Agro-Pastoral Ecotone in Northern China

Young elm trees belt-pumpkin strip intercropping was studied to solve the actual problem of resource losses in the large barren area resulted from reconverting cultivated land into forest in the agro-pastoral ecotone in northern China. The final objective was to realize effective utilization of the barren land with both ecological improvement and economic development. Field experiments were conducted together with laboratory analysis. The results indicated that the soil moisture level was remarkably increased in young elm trees belt-pumpkin strip intereropping because the pumpkin vines covered the gap between pumpkin planting-furrow and elm trees belt. The water use efficiency of the intercropping system was increased by 23.7-163.3% as compared with the single cropping. Elm trees belt-pumpkin strip intercropping changed the sequential succession trend of the grasses growing in the gap of the pumpkin planting-furrow. The annual grasses become the dominant vegetation. The nutritive value as fodder and yield of the annual grasses were also increased remarkably. The biomass of pumpkin, elm trees and grasses under intercropping increased by 24.4, 28.4 and 144.4%, respectively, as compared with those under single cropping. The land use efficiency was increased by 132%. It was also indicated that the soil erosion from the intercropping land was not increased due to pumpkin plantation. The differences in the soil erosion among intercropped area, elm trees belt and pumpkin strip with single cropping were not remarkable. Therefore, it was concluded that young elm trees belt-pumpkin strip intercropping is an effective way to utilize the barren land between the young elm trees belt and realize synergistic enhancement of ecological benefit and economic profit.

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.

Evaluation of Land Reclamation and Implications of Ecological Restoration for Agro-pastoral Ecotone: Case Study of Horqin Left Back Banner in China

The agro-pastoral ecotone has been recognized as the main distribution area of reserved land resource for cultivation. Accordingly, clarifying this assumption, as well as concerting land reclamation and ecological restoration, is important to ensure food security and environmental improvement in the agro-pastoral ecotone. We selected Horqin Left Back Banner(HLBB) as the subject of our case study. The landscape ecological security pattern of this area was determined using the minimum cumulative resistance model. Over-cultivation, quantity of reserved land resource for cultivation, and changes in landscape indexes before and after land use adjustment were then analyzed. Over-cultivation is a serious problem in the agro-pastoral ecotone. Reserved land resource for cultivation is less than that considered previously, and the area of reserved land resource for cultivation in HLBB only accounts for 11.50% of total uncultivated land. With regard to changes in landscape indexes, the adjusted land use pattern is effective for anti-desertification. The compensation standard for abandoned cultivated land should be improved and the comprehensive results of ‘Grain for Green' should be evaluated to further implement ecological restoration in the agro-pastoral ecotone.

生态交错带（Ecotone）理论研究进展

生态交错带（Ｅｃｏｔｏｎｅ）理论研究进展高洪文（东北师范大学草地研究所，长春１３００２４）ＡｄｖａｎｃｅｍｅｎｔｏｆＴｂｅｏｒｅｔｉｃａｌＲｅｓｅａｒｃｈｉｎＥｃｏｔｏｎｅ．￥ＧａｏＨｏｎｇｗｅｎ（ＩｎｓｔｉｔｕｔｅｏｆＧｒａｓｓｌａｎｄＲｅ－ｓｅａ...

生态环境脆弱带ECOTONE的基础判定

ECOTONE为国际生态界最近重新定义的基本概念之一。本文在诠释生态环境脆弱带的定义之后,对其实质及其空间属性作了较全面的逻辑归纳。在进一步研究的基础上,对于生态环境脆弱带作出了独立的函数表达,并且就生态环境脆弱带的宽度指标、重迭度指标、脆弱度指标、综合性指标,提出了较严格的表述形式。它们吸收了生态界面理论,并把系统生态学中的非稳定性理论,广延为辨识“全球变化”的基本手段,从而在生态学理论与应用两个方面,体现了研究的意义和价值。

Vertical and temporal distribution of nitrogen and phosphorus and relationship with their influencing factors in aquatic-terrestrial ecotone:a case study in Taihu Lake,China

Vertical and temporal distributions of N and P in soil solution in aquatic-terrestrial ecotone （ATE） of Taihu Lake were investigated, and the relations among N, P, ORP （oxidation reduction potential）, TOC, root system biomass and microorganism were studied. As a whole, significant declines in TN, NO3^--N, DON （dissolved organic nitrogen） and TP concentration in soil solution have occurred with increase of the depth, and reached their minima at 60 cm depth, except for NH4^＋-N, which increased with depth. The concentration of TP increased gradually from spring to winter in the topsoil, the maximum 0.08 mg/L presented in the winter while the minimum 0.03 mg/L in spring. In the deeper layer, the concentration value of TP fluctuated little. As for the NO3^--N, its seasonal variation was significant at 20 cm depth, its concentration increased gradually from spring to autumn, and decreased markedly in winter. Vertical and temporal distribution of DON is contrary to that of NO3^--N. The results also show that the variation of N and P in the percolate between adjacent layers is obviously different. The vertical variation ofTN, TP, NO3^--N, NH4^＋-N and DON is significant, of which the variation coefficient of NO3^--N along the depth reaches 100.23%, the highest; while the variation coefficient of DON is 41.14%, the smallest. The results of correlation analysis show that the concentration of nitrogen and phosphorus correlate significantly with TOC, ORP, root biomass and counts of nitrifying bacteria. Most nutrients altered much from 20 to 40 cm along the depth. However, DON changed more between 60 and 80 cm. Results show that soil of 0-60 cm depth is active rhizoplane, with strong capability to remove the nitrogen and phosphorus in ATE. It may suggest that there exists the optimum ecological efficiency in the depth of above 60 cm in reed wetland. This will be very significant for ecological restoration and reestablishment.

Current vegetation dynamics of the “forest-mountain tundra” ecotones of Lake Baikal coastal ranges

During last decades, new trends appeared in the ecotones of the upper boundary of forests at the ridges surroundingLakeBaikal(Khamar-Daban and Baikal’sky Ridge): ones to advance of wood species (Pinus sibirica Du Tour, Abies sibirica Ledeb., Larix sibirica Ledeb., Larix dahurica Lawson) out of timber stands into the area of subgoltsy with Pinus pumila (Pallas) Regel. up to mountain tundras. In average, this is from 100 to 200 - 300 meters (maximum up to500 m) in linear distance from the margin of dense timber stand. A burst of forests renewal occurred in 1989-1995, it resulted probably from a high productivity of the seeds of wood species due to warmer winters in 1980ies-1990ies which favoured the formation of favourable climate-edaphic conditions for the development of forest communities above the forests boundary on the ridges surrounding Lake Baikal.

Impacts of revegetation management modes on soil properties and vegetation ecological restoration in degraded sandy grassland in farming-pastoral ecotone

Focusing on the impact of various vegetation management modes on sandy grassland's soil property and vegetation ecological restoration of farming-pastoral ecotone,field surveys and lab analysis were conducted to study the correlation between the characteristics of soil properties and vegetation ecological restoration under four different vegetation management modes,i.e.,unenclosed natural restoration,enclosed natural restoration,unenclosed artificial restoration and enclosed artificial restoration,which have a restoration history of 15 years in the southern edge of the degraded sandy land area of Mu Us Desert in Leilongwan Town,Hengshan County,Shaanxi Province.After 15 years of vegetation restoration,these four vegetation management modes all proved to be useful for improving the vegetation ecological restoration and the soil quality of the degraded sandy grassland not only by enhancing the aboveground vegetation height,coverage and biomass but also increasing the content of soil clay,organic matter,CEC,total nitrogen,available nutrient while reducing soil bulk density.The vegetation ecological restoration effect and soil quality under enclosed or artificial restoration management are better than those of unenclosed or natural restoration management;and the most satisfactory vegetation ecological restoration effects and soil quality can be achieved under the integration of enclosed and artificial restoration management.Severely degraded sandy grassland,during the vegetation restoration,would form an interactional coordinating relationship with the vegetation and soil properties.Vegetation properties as height,coverage and biomass have significant positive correlations with organic matter,CEC,total nitrogen and available nitrogen,phosphorus,and potassium contained in soil.Only the adoption of the strict enclosure system,implementation of aggressive artificial vegetation restoration measures and the realization of the regurgitation-feeding policy of industry towards husbandry can guarantee the gradual restoration of degraded sandy grassland in farming-pastoral ecotone,so that it can continue to play the role of ecological protective screen.

Exploring the spatio-temporal impacts of farmland reforestation on ecological connectivity using circuit theory:A case study in the agro-pastoral ecotone of North China

Farmland reforestation can contribute substantially to ecological restoration.Previous studies have extensively examined the ecological effects of farmland reforestation,but few of them have investigated the spatiotemporal responses of broad-scale landscape connectivity to reforestation.By using a typical agro-pastoral ecotone in northern China as a case study,we addressed this issue based on an innovative integration of circuit theory approach and counterfactual analysis.The forest connectivity through multiple dispersal pathways was measured using the circuit theory approach,and its spatiotemporal changes after reforestation were evaluated by counterfactual analysis.The results showed that from 2000–2015,the reforested farmland occupied 2095 km^2,and 12.5% was on steeply sloped land.Farmland reforestation caused a greater increase in ecological connectivity by adding new ecological corridors and stepping stones in scattered forest areas rather than in areas with dense forest distributions.The newly added corridors and stepping stones were fragmented,short and narrow and thus deserve powerful protection.Future reforestation to improve landscape connectivity should highlight pinch point protection and obstacle removal as well as the tradeoff between farmland loss and farmer survival.Our findings are expected to inform the optimization of the Grain for Green policy from the perspective of broad-scale biodiversity conservation.

Ecological suitability evaluation for urban growth boundary in red soil hilly areas based on fuzzy theory

The fuzziness exists in spatial distribution of geographic data of land suitability evaluation processes,which makes it difficult to quantify land boundaries by using traditional binary logic-based overlay model.Aiming at this limitation,an ecological suitability evaluation analysis model was presented based on fuzzy theory and a research on urban growth boundary(UGB) of the Great-Hexi Leading District(GHLD) of Changsha was conducted.With the support of GIS,RS and MATLAB,slope,elevation,vegetation,soil productivity,soil permeability,water body and land use are selected as the input of model according to the characteristic properties of soil and terrain in red soil hilly areas.The running result of this model indicates that the ratios of highly suitable land,suitable land,moderately suitable land and unsuitable land in GHLD are 18.75%,10.31%,64.16%,6.78%,respectively.This result accords with spatial structure worked out by Space Development Strategy Planning of GHLD,Based on this result,several suggestions are made to guide UGB developments in future.

基于生态系统完整性的自然保护地边界划定方法--以欧美地区的实践为例

科学划定自然保护地的边界关系到保护目标的实现和管理措施的制定,是自然保护地规划和建设的首要环节。该文以欧美地区的实践案例为例,介绍了基于生态系统完整性的自然保护地边界划定方法。首先对现有自然保护地边界划定方法进行梳理,在此基础上介绍了面向实施的景观单元(Operational Landscape Units)的概念和划定流程;其次梳理了韦斯特布鲁克圩田保护边界划定和旧金山湾海岸带保护边界划定的案例;最后为我国自然保护地的边界划定提出建议。

农牧交错区草地生物多样性研究进展:方法、挑战、不足与展望

土地利用变化是生物多样性丧失的主要驱动因素,农牧交错区耕地-草地界面变化对草地生物多样性有显著影响,系统梳理相关研究进展,对于区域可持续发展至关重要。本文首先从空间尺度、研究层次、研究方法和应用决策4个角度对农牧交错区草地生物多样性研究进展进行了系统阐述,然后分析了当前农牧交错区草地生物多样性保护面临的挑战和机遇,最后就目前已有研究的局限性和未来的发展方向进行了探讨。研究表明,当前农牧交错区“耕地-草地界面变化对生物多样性影响”的研究十分薄弱,研究层次有待扩展、跨尺度集成研究亟须加强。未来应当融入空天地一体化的遥感监测技术,系统推进农牧交错区草地生物多样性研究,在全面理解影响机制的基础上,探索耕地粮食生产和草地生物多样性保护的双赢方案,促进区域可持续发展。

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.

树线交错带植物形态结构和生理生态学特性研究进展

由于复杂特殊的生长环境,树线交错带植物形成了独特的形态结构和生理生态学特性。本文综述了国内外学者在树线交错带植物形态适应特征、解剖结构特征、生理生态学特性等方面的研究进展,并提出研究展望,为进一步探究全球气候变化情况下植物对环境的响应机理及间接预测气候变化提供参考。

中国北方农牧交错带净初级生产力时空分异特征

为了解我国北方农牧交错带自然环境条件下的植被群落生产能力.基于2000—2020年的遥感数据和气象数据,利用光能利用率模型(CASA)估算了北方农牧交错带内植被净初级生产力(NPP),并对时空特征变化进行分析.结果表明:(1)北方农牧交错带内多年年均植被NPP,在东北部呈中间低四周高的分布;而在中南部植被NPP的分布呈现自南、东南向北、西北减少的分布特征.(2)2000—2020年北方农牧交错带单位面积年均植被NPP为234.33 gCm^(-2)a^(-1),年均植被NPP总量为167.90×10^(12)gCm^(-2)a^(-1).(3)研究时间段内植被NPP变化以波动增加为主,其变化范围190.91~284.09 gCm^(-2)a^(-1);与2000年相比,2020年NPP增加了42.05%.(4)植被NPP增加的区域占总面积的86.98%;减少的区域占总面积的2.06%.植被NPP的时空分布特征表明了中国北方农牧交错带内植被生态系统整体得到改善.

一种基于多维度生态评估的自然保护地边界优化方法——以三江源国家公园黄河源园区为例

科学准确划定自然保护地边界是设立保护地及制定和实施保护管理措施的首要前提,厘清自然保护地边界是在整合优化自然保护地的过程中首要解决的问题。以生物多样性与生态系统服务双保护为目标,基于In VEST和SWAT模型综合评估生态系统服务,并基于生物完整性等级(Degree of Biological Integrity,DBI)和生态增强因子(Enhancement Factor,EF)评估了保护成本及生态效益,提出了一种自然保护地的边界优化方法。基于这种方法将三江源国家公园黄河源园区的现有边界优化为涵盖总体自然边界、核心生态边界与管理边界的多重边界,从而使生态系统服务得到最大限度的保护,使生物多样性保护得到一定程度的加强,并同时考虑管理效益,确保新增保护成本较低。

“三治”融合的边界弹性与机制创新研究

乡村治理有效需要自治、法治和德治的有机融合,“三治”融合是塑造良好乡村政治生态的关键。当前乡村治理的痛点突破口亟需厘清自治、法治与德治的边界弹性空间,推动乡村治理创新在人本边界、制度边界和情感边界允许的范围内运行。基于福建省晋江市大埔村“三治”融合的个案考察,对其运用边界弹性促进乡村治理有效的模式进行分析。研究发现:“三治”融合的机制创新在于,以整体性治理的视角建立创新边界机制、优化乡村政治生态、持续推进深度融合的路径,推动高质量的“三治”融合引领乡村治理现代化。

多重边界地带的社会生态:以明清时期巴东县为中心

明清时期的巴东是一个由政区边界、文化区边界和民族区域边界等多重边界所构成的复杂社会,在政治、交通、土汉矛盾和文化辐射等多种因素的综合作用下,形成独特的社会生态。一方面,巴东地处四川与湖北两省边界,行政上隶属湖北,民间文化则深受巴蜀文化影响;另一方面,巴东地处经制政区与土司辖区交界,社会环境夷夏相半,导致前里、后里在语言、风俗、经济和社会矛盾等方面存在较大差异。巴东县域的地理位置和多重边界属性,增加了地方治理的难度和成本,明清政府把治理成本转嫁给巴东本地,从而增加了巴东的社会压力,导致社会风气逐渐衰败。

THE BOUNDARY LAYER ECOLOGY-A NEW AND DEVELOPING BRANCH OF ECOLOGY

The paper concems objects are the functional leaves of Populus davidiana three years old in natural environental. We discuss mainly the structure, function, motional law of the ecological boundary and its ecological effects.

农牧交错带生态与生产用地时空转换及其驱动因素分析——以张家口坝上地区为例

为实现农牧交错带生态用地与生产用地的协调发展,提升区域生态功能,以张家口坝上地区为例,构建土地利用转移矩阵,利用地理集中度和地理探测器模型,揭示生态用地与生产用地时空变化、转换特征和驱动因素。结果表明:(1)2000—2020年,张家口坝上地区生态用地规模增加了5.41%,表现为先增后减的变化趋势,生产用地规模减少了6.89%,表现为先减后增的变化趋势。(2)生态用地和生产用地之间相互转换频繁,生产用地向生态用地转换了21.23×10^(4)hm^(2),转换数量逐渐减少,自然条件较好地区(降雨量多、海拔低和坡度缓等)的生产用地开始向生态用地转换;生态用地向生产用地转换了12.47×10^(4)hm^(2),转换数量逐渐增加,且自然条件较恶劣地区的生态用地开始向生产用地转变。(3)土壤有机质、人均耕地面积和坡度等是影响生产用地向生态用地转换的主要因素,土壤有机质与人均耕地面积的交互作用解释力最大;土壤有机质含量低、人均耕地面积多、坡度6°~15°和年均降雨量低于400 mm的地区容易发生生产用地向生态用地转变。坡度、年均降雨量和人均耕地面积等是影响生态用地向生产用地转变的主要因素,坡度与地貌类型的交互作用解释力最大;在坡度2°~6°较缓区、年均降雨量大于400mm、人均耕地面积少的地区容易发生生态用地向生产用地转变。研究区近年来出现生态用地向生产用地的转换应引起重视。