海口市建设用地生态适宜性研究

选取海口市建设用地作为研究对象, 基于2010 年Alos 遥感影像数据, 利用层次分析法和GIS 空间叠加分析法对研究区建设用地生态适宜性进行评价。结果显示: 研究区生态适宜性评价等级为“最适宜”和“适宜”用地仅占全区总面积的14.06%, 所占比例较小, 主要分布在城镇建成区及周边临近区域;“基本适宜”用地占全区总面积的19.77%, 面积较大分布不集中且范围较广;“不适宜”和“很不适宜”两者总比例占整个研究区总面积的44.64%, 所占比例较大, 主要分布在偏远郊区及植被茂密的区域; “不可用地”为21.54%, 主要分布在红树林自然保护区、基本农田保护区、高速公路沿线、海岸带、特殊用地及风景名胜区。研究区建设用地生态适宜性整体比较低, 总体分布规律呈现为南低北高; 依照生态适宜性分析结果, 提议在不同区域合理开发土地资源; 建议加强对区域生态环境的保护并严格控制“禁建区”和“限建区”的开发行为。     

天山北坡经济带关键性生态空间评价

关键性生态空间在生态系统中所发挥的基础性和保障性功能尤为重要,其范围辨识及评价研究对于国土安全和区域可持续发展具有重要意义。以天山北坡经济带为研究区,构建适于西北寒旱区脆弱敏感环境的关键性生态空间评价体系,借助GIS和RS技术,从生态系统服务功能重要性和敏感性两方面对其空间范围进行辨识和分级评价,并进行土地利用生态安全冲突分析。研究结果表明:(1)底线型和危机型生态空间作为研究区的关键性生态空间,面积为45318km²,占比53%,主要分布于南部山区、农垦区西部及北部沙漠/荒漠区;(2)生态系统服务功能与植被显著相关,较重要、重要和极重要区域共占约20.9%,集中在南部山前草原及中部农垦区,生态系统服务功能整体较弱,主导因子为水源涵养和生物多样性保护功能;(3)研究区生态系统敏感性等级主要以中度敏感为主,敏感和极敏感区域面积占比37.7%,分布于高山区、荒漠戈壁区和低山与绿洲过渡区,主要体现为土地沙化和土地盐渍化。(4)全区土地利用生态安全冲突等级较高,有45%的城建用地与56.5%的耕地占用关键性生态空间。本研究可为区域国土空间布局和生态格局优化提供参考,并对相关理论和实证研究起到补充和借鉴作用。     

桂西北喀斯特地区生态系统服务功能重要性评价与空间分析

生态系统服务功能重要性评价对于明确区域生态系统服务功能空间分布规律,进行生态功能区划有重要意义.本文根据桂西北喀斯特地区的主要生态系统服务功能,选取生物多样性保护、土壤保持、水源涵养、石漠化控制和产品提供5项服务功能,采用层次分析法和多因子综合评价法建立指标体系,在GIS技术支持下,分析了5项生态系统服务功能的重要性及其空间分布特征,并进行了综合评价.结果表明:桂西北喀斯特地区生态系统服务功能重要性程度较高,其中极重要、中等重要地区面积占研究区总面积分别为25.2%和33.4%;喀斯特地区生态系统土壤保持功能和石漠化控制功能对喀斯特区域生态环境具有重要控制作用,其分布区域是桂西北喀斯特地区生态环境治理和生态恢复的重点区域;明确了桂西北喀斯特地区生态系统生物多样性保护功能、水源涵养功能及产品提供功能的重要性等级及空间分布特征,为喀斯特地区生态系统的科学管理和生态功能区划提供重要依据.     

山东省安丘市生态用地动态变化

利用山东省安丘市4期土地利用数据,通过动态度、转移矩阵及不稳定斑块空间分析等方法,研究了该县域生态用地动态变化特征,以期对该地区新农村建设的可持续发展和生态环境保护提供决策参考。结果表明:1995—2010年安丘市生态用地占市域面积比例由14.04%降低至13.31%,草地、水域减少,林地、未利用地增加,而非生态用地中建设用地持续增加、耕地持续减少。3个时段,不稳定斑块占研究区总面积比重较小,分别为1.39%、2.21%和3.13%;不稳定斑块中生态用地面积及斑块数量所占比例分别为31.09%、43.21%、20.52%和28.24%、34.06%、11.28%。生态用地空间稳定性相对较低,且有下降趋势。Moran指数表明,转入的生态用地呈聚集分布,转入的非生态用地呈离散或随机分布。生态用地与非生态用地的空间动态度持续增加,整体上生态用地朝着规模减小的方向发展,非生态用地朝着规模增大的方向发展。     

基于GIS的秦岭山区聚落用地适宜性评价

利用自然地理、生态和社会经济方面共14个因子构建秦岭山区聚落建设用地适宜性评价指标体系,采用AHP法确定各评价因子的权重,在地理信息系统(GIS)和遥感(RS)技术支持下,利用适宜性评价模型定量评价聚落建设用地适宜性,将聚落建设用地适宜性分为五个等级,并结合已建设区进行空缺分析。结果表明:(1)秦岭山区最适宜聚落用地面积为3378.1 km2,占研究区总面积的5.87%,说明秦岭山区适宜聚落开发的土地相对较少。(2)最适宜聚落用地集中在秦岭北、南坡山麓和东部的山间河谷地带,山地型特征明显。(3)有9.15%已建成区分布在限制建设区内,存在生态安全风险。(4)可用适宜聚落建设用地为3192.27 km2,空间分布不平衡。研究结果可为该区域城镇体系布局与用地规模的核算提供科学依据。     

基于潜力-约束模型的冀中南区域建设用地适宜性评价

区域建设用地适宜性评价是区域规划空间布局的重要前提和基础,是区域土地资源合理利用的重要依据.基于GIS软件平台,采用区域综合实力与空间可达性分析方法对冀中南区域发展潜力进行了空间定量分析,采用生态环境敏感性方法对研究区发展的生态约束进行定量评价,进而借鉴损益分析法,构建了由发展潜力和生态约束构成的潜力-约束模型,并通过相互作用判别矩阵,得到不同发展理念下的建设用地适宜性情景方案.结果表明： 研究区综合实力与空间发展潜力均呈首位分布,且点轴发展模式明显;生态环境敏感性总体上呈西高东低的分布格局;区域经济发展理念对区域生态安全格局和城市建设用地增长空间规模具有重要影响.潜力-约束模型重新构建了区域用地发展适宜性的评判原则与方法,能够较为科学地实现区域综合发展潜力的空间栅格化,获取研究区未来用地的发展趋势和空间布局,可以为城市与区域规划提供科学依据,是实现区域“精明增长”与“精明保护”的有效途径.     

基于GIS的关键性生态空间辨识——以鄱阳湖生态经济区为例

生态空间承担着维持区域生态平衡的使命,并为社会提供持续不断的生态空间服务,是区域土地生态能持续地提供自然空间服务的基本保障。以自然生态环境脆弱的鄱阳湖生态经济区为研究区,结合国内外学者的相关实践经验和研究成果,基于RS和GIS等相关空间信息技术,通过生态系统服务功能重要性评价和生态系统敏感性评价方法,因地制宜地选取了相应评价指标,以栅格为单元辨识了鄱阳湖生态经济区关键性生态空间。研究结果表明:鄱阳湖生态经济区关键性生态空间面积为27751.25 km~2,占研究区总面积的52.55%,其中底线型生态空间面积为17125.31 km~2,占研究区总面积三分之一,危机型生态空间面积为4431.19 km~2,占研究区总面积的8.39%,缓冲型生态空间面积为6194.75 km~2,占研究区总面积的11.73%。在现状土地利用生态安全冲突分析中,有14.29%的耕地、9.31%的建设用地处于关键性生态区内。     

基于最小累积阻力模型的北京市生态用地规划研究

生态用地规划强调对区域生态系统结构与功能的保护,增强社会经济发展的生态环境支撑能力。从保障首都基本生态安全、改善大气环境质量、建设宜居城市的角度出发,通过对北京市生态重要性进行综合评价,明确北京市重要生态用地空间分布特征。在此基础上,采用最小累积阻力模型(MCR),以重要生态用地为"源",以土地覆被类型、距道路距离和距居民点距离作为阻力因子生成阻力面,模拟重要生态用地空间扩张过程,进而设置生态用地规划情景,并从景观连通性、生态功能保障度及与现状建设用地冲突情况等3个方面对不同情景下的生态用地规划方案进行保护效能评价,最终提出北京市生态用地的适宜规模和优化布局方案。研究结果表明:北京市重要生态用地总面积为9879 km~2,占市域总面积的60.20%;生态用地的适宜规模为12417 km~2,占市域总面积的75.67%,其中,平原区生态用地的适宜规模为2944 km~2,占平原区总面积的46.45%,主要分布于建成区的外围过渡地带;山区生态用地的适宜规模为9473 km~2,占山区总面积的94.05%。     

基于开发区规划环评的土地资源承载力评价

土地资源承载力评价是规划环境影响评价的重点,是决定规划是否可以实施的重要依据.基于地理信息系统技术的空间分析功能,选取高程、坡度、土地利用现状、距居民点距离、距主要交通道路距离和距环境敏感区距离作为敏感因子,综合评价了漳州招商局经济技术开发区生态敏感性程度及其空间分布状况,并将评价结果与用地布局规划图叠加进行生态适宜性分析.结果表明： 研究区84.0%的居住用地、93.1%的工业用地、86.0%的交通用地和760%的其他建设用地处于非敏感区和一般敏感区,用地规划实施总体上对区域陆域生态环境造成的影响较小,规划区内土地资源可以满足规划用地需求.以生态用地为约束条件进行人口承载力评价的结果表明,高度敏感区和60%的中度敏感区可视为生态用地,开发区规划期内人口规模为24.0万,区域人均用地可达134.0 m2,该人口规划规模适宜,符合相关建设用地标准.     

基于NPP的重庆市“一圈两群”生态系统服务重要性评价及其机理研究

生态系统服务功能重要性的研究可为生态功能定位及生态环境的建设和保护提供重要的科学依据。采用NPP定量指标评价法, 评价重庆市2018年水源涵养服务、水土保持服务、生物多样性服务与生态系统综合服务重要性, 识别生态系统服务热点区域, 从土地利用及主控因子识别方面对重庆市“一圈两群”发展格局下生态系统服务功能进行综合研究, 揭示研究区生态系统服务重要性的内在机理。结果表明:(1)水源涵养与生物多样性重要性级别中, 重庆市主城区都市圈级别较低, 渝东南武陵山区城镇群和渝东北三峡库区城镇群级别较高, 水土保持重要性级别则相反。(2)重庆市生态系统综合服务中等重要区域面积最大, 占总面积的44.70%, 一般重要区域面积最小, 占比4.92%, 空间上呈现出中部及东南部较高, 西北部较低的分布态势; (3)研究区一类服务热点区占总面积的39.6%, 主要分布在主城区都市圈的西北和东南处, 二类占35.3%, 主要分布在渝东南城镇群的西南处和渝东北城镇群的东南处, 三类占6.8%, 零散分布于渝东北城镇群; (4)耕地与林地在研究区整体与各区域的生态系统综合服务重要性级别中占比最大, 均为不同重要性级别区域的主要用地类型; (5)研究区生态系统服务重要性各级别区域内主控因子存在差异, 但NPP、坡度、海拔对研究区生态系统综合服务重要性结果影响较大。客观评价和揭示了重庆市生态系统服务功能在重要性特征及其内在机理, 以期为重庆市分区发展过程中的生态保护提供科学依据及理论支持。     

Spatial and seasonal variation in nutrient excretion by benthic invertebrates in a eutrophic reservoir

1. Nitrogen (N) and phosphorus (P) fluxes via excretion by benthic invertebrates were quantified in a eutrophic reservoir (Acton Lake, Ohio, U.S.A.). We quantified variation in nutrient fluxes seasonally (June until November 1997), spatially (three sites) and among taxa (chironomids, tubificid oligochaetes and Chaoborus). 2. The three taxa differed in spatial distribution and contribution to nutrient fluxes. Tubificids were the most abundant taxon at two oxic sites (1.5 and 4 m depth), and were exceedingly rare at an anoxic, hypolimnetic site (8 m). Chironomids were abundant only at the shallowest oxic site. Chaoborus was the only abundant taxon at the anoxic site. Total benthic invertebrate biomass was greatest at the shallowest site and lowest at the anoxic, hypolimnetic site. 3. Mass‐specific excretion rate [μmol NH₄–N or soluble reactive P (SRP) excreted mg dry mass^–1 h^–1] varied among experiments and was influenced by temperature. Differences among taxa were not significant. Thus, nutrient flux through benthic invertebrates was affected more by total invertebrate biomass and temperature than by species composition. 4. Fluxes of N and P via benthic invertebrate excretion (μmol NH₄–N or SRP m^–2 day^–1) were greatest at the oxic sites, where fluxes were dominated by the excretion of tubificids and chironomids. The N and P fluxes at the anoxic site were much lower, and were dominated by excretion by Chaoborus. The ratio of N and P excreted by the benthic invertebrate assemblage varied seasonally and was lowest at the anoxic site. 5. Comparison with other measured inputs shows that excretion by benthic invertebrates could be an important source of nutrients, especially of P. However, the relative importance of nutrient excretion by the benthos varies greatly spatially and temporally.     

在杉木林和马尾松林中雨水的养分淋溶作用

本试验地是在杉木林和马尾松林中,主要对降雨和径流水中所含各种养分物质进行测定。结果表明:降雨的养分含量与降雨量存在着半对数函数关系。降雨输入林地的养分量显著地大于径流输出的养分量。林内雨和树干茎流淋溶的养分量占养分还原总量的48—53％。林内雨和树干淋溶的K、Mg、N养分物质量超过凋落物归还养分量。     

Nutrient transport in mycorrhizas: structure,physiology and consequences for efficiency of the symbiosis

Nutrient transport in mycorrhizas occurs across specialized interfaces which are the result of corrdinated development of the organisms. The structural modifications give rise to large areas of either inter- or intra-cellular interface in which wall synthesis is frequently modified and in which altered distribution of membrane bound ATPases is important, particularly with respect to mechanisms that may be involved in bidirectional transfer of nutrients. Except in orchid mycorrhizas, net movement of organic carbon from plant to fungus occurs, complemented by mineral nutrient movement in the opposite direction. The general consensus is that sustained transfer at rates that will maintain the growth and development of the organisms requires increases in the rates at which nutrients are lost from the organisms; possible mechanisms for this are discussed. The transfer processes are essential in determining both plant and fungal productivity and an approach to calculating the efficiency of the symbiosis in terms of the expenditure of carbon (or of phosphorus) is discussed.     

Sources of nutrients to rooted submerged macrophytes growing in a nutrient-rich stream

1. The relative contribution of roots and leaves to nutrient uptake by submerged stream macrophytes was tested in experiments where plants were grown in an outdoor flow-channel system. Water was supplied from a nutrient-rich stream with inorganic nitrogen and phosphorus concentrations typical of Danish streams.
2. Four submerged macrophyte species were tested, Elodea canadensis , Callitriche cophocarpa , Ranunculus aquatilis and Potamogeton crispus, and all species were able to satisfy their demand for mineral nutrients by leaf nutrient uptake alone. This was evident from manipulative experiments showing that removal of the roots had no negative impact on the relative growth rate of the plants. Further, the organic N and P concentrations of the plant tissue was constant with time for the de-rooted plants.
3. Enrichment of water and/or sediment had no effect on the relative growth rate of two species, E. canadensis and C. cophocarpa , indicating that in situ nutrient availability was sufficient to cover the needs for growth. Despite the lack of a response in growth rate, a reduced root/shoot biomass ratio was observed with nutrient enrichment of water and/or sediment, and an increased tissue-P concentration in response to open-water enrichment.
4. The open-water nutrient concentrations of the stream in which the experiments were performed are in the upper part of the range found for Danish farmland streams (the majority of Danish streams). Still, however, the negligible effect of nutrient enrichment on the growth of submerged macrophytes observed suggests that mineral nutrient availability might play a minor role in controlling macrophyte growth in most Danish streams.     

Optimizing nutrient management for farm systems

Increasing the inputs of nutrients has played a major role in increasing the supply of food to a continually growing world population. However, focusing attention on the most important nutrients, such as nitrogen (N), has in some cases led to nutrient imbalances, some excess applications especially of N, inefficient use and large losses to the environment with impacts on air and water quality, biodiversity and human health. In contrast, food exports from the developing to the developed world are depleting soils of nutrients in some countries. Better management of all essential nutrients is required that delivers sustainable agriculture and maintains the necessary increases in food production while minimizing waste, economic loss and environmental impacts. More extensive production systems typified by 'organic farming' may prove to be sustainable. However, for most of the developed world, and in the developing world where an ever-growing population demands more food, it will be essential to increase the efficiency of nutrient use in conventional systems. Nutrient management on farms is under the control of the land manger, the most effective of whom will already use various decision supports for calculating rates of application to achieve various production targets. Increasingly, land managers will need to conform to good practice to achieve production targets and to conform to environmental targets as well.     

缺苞箭竹密度对养分元素贮量、积累与分配动态的影响

研究了缺苞箭竹(Fargesiadenudate)-紫果云杉(Piceapurpurea)原始林下不同密度缺苞箭竹群落的养分元素贮量与分配动态以及养分元素在一个生长季节内的积累量。结果表明:地上、地下部分的N、P、K、Ca、Mg贮量均随着箭竹密度的增加而增大,养分元素贮量排序为:K>N>Ca>P>Mg。密度较大的箭竹群落(D1和D2)中,地上部分的N、P和K贮量大于地下部分,而密度较小的箭竹群落(D3)中P和K贮存于地下部分的比例较大,3个群落中的地下部分Ca和Mg贮量均大于地上部分,且地下部分的养分元素贮量的比例随着箭竹密度的增加而减少。养分元素的总积累量排序为:K>N>Ca>P>Mg,且地上部分和群落的总积累量随着箭竹密度的增加而增加,总积累率以D1群落最大,3个群落的养分元素积累率大小顺序为:Mg>Ca>P>N>K。地下部分(根系和鞭)养分元素贮量比例随着箭竹密度的增加而下降,而地上部分(叶、枝和竹杆)养分元素贮量比例随着箭竹密度增加而上升。密度对缺苞箭竹养分贮量、积累和分配动态有深刻影响。     

Constructing nutrient budgets

We present a formalised, yet flexible, scheme for classifying and symbolising the components of nutrient budgets. The scheme distinguishes hierarchically both among components of the ingesta and among the various sinks to which they are allocated. The primary terms in the budget are distinguished according to either methodological criteria (whether in a given time period they are retained by the animal or dissociated from the body) or functional criteria (whether they contribute to fitness). In both methodological and functional classifications, the primary terms of the budget may be progressively expanded to represent with increasing resolution nutrient allocation. The interplay between the various components of the ingesta and their subsequent allocation may be considered simultaneously using a two-dimensional nutritional matrix.     

不同施肥模式下潮棕壤稻田的速效养分状况和水稻的养分分配

研究了不同施肥模式下下辽河平原潮棕壤稻田土壤速效养分的供应能力及水稻的养分分配.结果表明:各处理0～20 cm速效养分供应能力均高于20～40 cm,其变异也大于20～40 cm(速效氮除外);有机、无机肥相结合有利于提高土壤速效养分的供应能力;水稻氮和磷的分配主要集中在籽实中,钾的分配则主要集中在秸秆中.采用秸秆还田措施有利于缓解钾肥资源的不足,保持钾素的循环再利用,维持土壤钾库,减少钾肥投入,降低农业生产成本,减轻环境污染.