民勤沙井子绿洲边缘区防护林景观结构分析及评价

本文运用景观生态学和防护林学原理 ,经 GIS系统的数据处理 ,对沙井子绿洲边缘区防护林体系的组成、结构、功能进行了分析 ,并对该区的防护林体系景观布局进行了综合评价 ,提出在该地区发展生态经济型防护林体系的方法及改造措施     

基于水资源承载力的内陆河流域城镇发展及其生态效应研究框架——以黑河流域为例

本文从现实出发,在分析内陆河流域城镇发展与水资源承载力关系的基础上,构建了内陆河流域城镇体系发展的水资源承载力与生态效应的总体研究框架,提出了研究目标、思路和内容。指出要以可持续发展理论为指导,以水资源为主脉,以山地—绿洲—荒漠景观格局为底质,在分析水—绿洲—城镇体系空间耦合关系的基础上,探讨干旱区内陆河流域城镇体系发展的内在机制和特殊规律;不同时空条件下水资源的人口、城镇、经济承载力,建立不同边界条件下水资源有效转移和优化配置的模拟模型;通过对城乡人口迁移过程和机理分析,产业聚集、转型分析和绿洲-荒漠景观格局分析,构建与水资源承载力相适应的城镇体系发展规模、职能状态和空间自组织结构;揭示城镇发展与环境演变协同作用下流域不同时空的生态经济效应。     

绿洲景观生态建设的理论思考

本文以新疆绿洲为例 ,详细讨论了绿洲景观内当前存在的主要环境问题的危害与成因 ,并针对这些问题 ,以景观生态学原理为指导 ,对绿洲景观生态规划进行了讨论 ,结果认为 ;对于绿洲景观而言 ,只要从加强排水系统工程建设、实现灌排配套 ;调整优化绿洲农业结构 ;完善和加强绿洲防护林体系建设和绿洲 -荒漠交错带建设 ,即可实现绿洲环境的可持续性 ,进而为绿洲经济的可持续发展创造条件     

黑河流域水资源开发的环境效应分析

水资源系统、农业生态系统和林草生态体系是构成干旱内陆河流域生态环境体系的特征因素。本文分析了黑河流域水资源开发利用引起的这三要素的变化，论述了流域综合环境效应的基本特征。     

基于GIS和RS的石羊河流域景观功能分区

景观功能分区是生态系统和自然资源科学管理及可持续利用的基础。干旱区内陆河流域生态系统组成要素和影响因素的区域差异性决定了不同区域具有不同的景观功能。对其进行科学划分,可为生态恢复与重建提供科学依据。针对目前生态功能区划仅从区域地貌单元、生态要素等方面考虑,而很少涉及景观能量循环运行与景观优化关注单元等景观生态学的内容。...     

新疆高标准防护林体系建设的理论和技术取向

新疆环境干旱 ,生态系统脆弱 ,防护林体系是不可缺少的生态成分。过去只注重了农田防护林体系的建设 ,系统目标和结构单一 ,不具有生态可持续性。高标准防护林体系建设要充实理论和技术体系的内容和方法。在理论方面要建立完善的目标系统 ,注重干扰体系的研究 ,把防护林体系建设上升到绿洲生态系统建设上来 ,区分生态系统的尺度性和等级性 ,通过自然斑块系统和生物多样性的保护 ,保障各等级生态系统的生态过程完整性。技术体系方面要注重系统规模性 ,通过恢复和重建自然斑块和廊道 ,小结构的合理格局来加强生态基础建设 ,实现生态的可持续性     

荒漠绿洲生态系统的景观格局分析--景观空间方法与应用

本文基于生态空间理论和景观格局分析指标,针对荒漠绿洲生态体系,以植被演替为主要生态变化表现以及受外来径流制约的特点,提出区域空间格网化,以网格为研究单元提取指标信息的景观格局分析方法,以黑河流域下游三角洲区域为研究实例,结果表明,该方法与土地利用类型划分景观类型的方法相比,景观类型与荒漠绿洲的生态构成相一致,能反映径流影响的景观结构与生态变化,便于生态保护规划与景观设计。     

喀什河流域景观生态综合评价研究

利用遥感技术对喀什河流域景观进行分析,综合景观密度、景观比例和优势度值三个指数构造了景观类型结构特征因子反映景观稳定性,应用生物生产力因子来反映生态稳定性,应用土地利用因子来反映人为活动影响水平,利用这三个因子借助综合指数法进行喀什河流域景观生态综合评价研究。结果表明:1)喀什河流域是以自然生态系统为主,伴有较轻人为干扰痕迹,生态系统的生物生产力和稳定性较好;2)流域景观生态质量为5级以上的占主体(82.08%),其中6级所占总面积的56.63%,说明景观生态较好。     

内蒙古牧区灌溉草场建设规模与格局评价

以内蒙古鄂尔多斯荒漠化草原鄂托克旗都思图河流域面积468km2为研究对象,对2006年和2007年流域内人工灌溉草场建设项目启动前后进行对比分析,研究流域内显性植被、隐性植被、玉米灌溉草场和苜蓿灌溉草场等资源斑块的景观特征,利用协调度进行牧区水利建设对整个流域生产力的影响进行评价。研究结果表明:牧区水利建设前后的景观格局由原来的随机型向集群型发展,景观的多样性、异质性、关联性、易达度、连通性下降,而景观斑块的分散度、干扰度、隔离度和破碎度等指数上升;景观资源斑块数量的消长与排列格局改变,直接导致流域内水资源亏缺近364.421mm,生物量下降53807.3 kg/a.hm2;景观在人工草场建设前后的协调度表明,在人工草场水利建设前其协调度评价值为63,而建设后其评价值仅为43。由此建议:以集群格局进行草原牧区水利建设不利于草原生态系统的稳定;草原水利建设应考虑草原本底-流域廊道-草库仑斑块在水流作用下能流、物流耦合的生态过程前提下,实现草原流域景观要素的水资源利用与分配;草原生产力提高的瓶颈是保证地表环境如何把天然降水转化为草原生产力层生态水,以维系正常的草原生产力。     

黑河流域中游农田防护林小气候效应

为进一步揭示农田防护林对小气候的影响,将设置于黑河流域中游农田防护林网内、外两个地面气象站8年的同步观测数据进行了定量比较分析,结果表明:夏季林网内日均、日最高、日最低气温比林网外低,而冬季林网内日均、日最高气温比林网外高,林网内昼夜温差比林网外大,林网内蒸发量仅为林网外的77.3%,林网内年均相对湿度大于林网外8%,林网形成的独特小气候,对水资源短缺的黑河流域地区具有重要的生理、生态及水文学意义;同时发现,林网内冬季、早春的昼夜温差、日最低、极端最低气温低于林网外,此刻的低温对越冬植物在休眠期、早春可能易受低温冻害。     

Understanding the impact of mountain landscapes on water balance in the upper Heihe River watershed in northwestern China

Estimating the impact of mountain landscape on hydrology or water balance is essential for the sustainable development strategies of water resources.Specifically,understanding how the change of each landscape influences hydrological components will greatly improve the predictability of hydrological responses to mountain landscape changes and thus can help the government make sounder decisions.In the paper,we used the VIC(Variable Infiltration Capacity)model to conduct hydrological modeling in the upper Heihe River watershed,along with a frozen-soil module and a glacier melting module to improve the simulation.The improved model performed satisfactorily.We concluded that there are differences in the runoff generation of mountain landscape both in space and time.About 50% of the total runoff at the catchment outlet were generated in mid-mountain zone(2,900-4,000 m asl),and water was mainly consumed in low mountain region(1,700-2,900 m asl)because of the higher requirements of trees and grasses.The runoff coefficient was 0.37 in the upper Heihe River watershed.Barren landscape produced the largest runoff yields(52.46% of the total runoff)in the upper Heihe River watershed,followed by grassland(34.15%),shrub(9.02%),glacier(3.57%),and forest(0.49%).In order to simulate the impact of landscape change on hydrological components,three landscape change scenarios were designed in the study.Scenario 1,2 and 3 were to convert all shady slope landscapes at 2,000-3,300 m,2,000-3,700 m,and 2,000-4,000 m asl respectively to forest lands,with forest coverage rate increased to 12.4%,28.5% and 42.0%,respectively.The runoff at the catchment outlet correspondingly declined by 3.5%,13.1% and 24.2% under the three scenarios.The forest landscape is very important in water conservation as it reduced the flood peak and increased the base flow.The mountains as "water towers" play important roles in water resources generation and the impact of mountain landscapes on hydrology is significant.     

Coupling between the Grain for Green Program and a household level-based agricultural eco-economic system in Ansai,Shaanxi Province of China

The implementation of the Grain for Green Program(GGP)has changed the development track of the agricultural eco-economic system in China.In response to the results of a lag study that investigated the coupling between the GGP and the agricultural eco-economic system in a loess hilly region,we used a structural equation model to analyze the survey data from 494 households in Ansai,a district of Yan’an City in Shaanxi Province of China in 2015.The model clarified the direction and intensity of the coupling between the GGP and the agricultural eco-economic system.The coupling benefits were derived through linkages between the program and various chains in the agricultural eco-economic system.The GGP,the agroecosystem of Ansai and their potential coupling effects were in a state of general coordination.The agroecosystem directly affected the coupling effect,with the standardized path coefficient of 0.87,indicating that the agroecosystem in Ansai at this stage provided basic material support for the coupling between the GGP and the agricultural eco-economic system.The direct path coefficient of agroeconomic system impacted on the coupling effect was-0.76,indicating that partial contradictions occurred between the agroeconomic system and the coupling effect.Therefore,although the current agroecosystem in Ansai should be provided sufficient agroecological resources for the benign coupling between the program and the agricultural eco-economic system,agricultural development failed to effectively transform agroecological resources into agricultural economic advantages in this region,which resulted in a relative lag in the development of the agricultural economic system.Thus,the coupling between the GGP and the agricultural eco-economic system was poor.To improve the coupling and the sustainable development of the agricultural eco-economic system in cropland retirement areas,the industrial structure needs to be diversified,the agricultural resources(including agroecological resources,agricultural economic resources and agricultural social resources)need to be rationally allocated,and the chain structure of the agricultural eco-economic system needs to be continuously improved.     

关中地区农业生态经济系统协调度时空动态分析

以关中地区1999~2008年农村社会经济指标数据为基础,参照农业生态协调度计算公式,结合关中地区实际情况,构建了评价指标体系,得出关中地区及其各地市的农业生态经济系统协调度和协调等级。结果表明:(1)1999~2008年,关中地区的农业生态经济协调度整体表现为从上升到近两年来下降的趋势,生态子系统协调度在波动中下降,经济和社会子系统的协调度除个别年份外,都处于较稳定的上升趋势;(2)关中各地市农业生态经济协调度整体表现为波动上升的趋势,但渭南市和杨凌区农业生态经济协调度的上升趋势最快,咸阳、宝鸡市次之,西安和铜川市的协调度上升趋势较慢;(3)农业生态经济系统中生态子系统的发展对地区农业系统协调度有抑制作用,经济子系统表现为促进作用,社会子系统则处于波动增长影响。针对关中地区生态和社会经济发展的现状特点,提出农业经济生态协调发展调控模式。     

乌兰布和沙漠绿洲不同生态功能区划分及其建设策略

绿洲是乌兰布和沙漠最重要的生态经济区域,绿洲寓于沙漠而异于沙漠。本文采用样线与样方相结合的方法,综合调查了绿洲-荒漠综合体的景观、地貌、植被、水土资源特征、经济活动及生态环境问题等因子,依据各因子特征的差异,将乌兰布和沙漠绿洲-荒漠综合体划分为绿洲生态经济核心区、绿洲—荒漠生态缓冲区和自然荒漠生态恢复区三个生态功能区;并论述了各功能区的特征、存在的生态环境问题,提出了不同生态功能区今后的建设方向和策略。     

大庆沙地景观生态建设

本文以大庆沙化土地为对象,应用景观生态学的人与自然共同创造、生物控制共生、生物圈等级组织、异质多样性理论,探讨景观生态建设理论在沙地建设中的应用,提出了大庆７种沙地景观生态建设设计方案。     

基于能值分析的甘肃农业生态经济系统发展态势及可持续发展对策

运用能值分析方法,对甘肃农业生态经济系统的能值产投结构、能值指标进行了计算,井从纵向和横向的比较中对甘肃农业生态经济系统发展水平进行了诊断.分析表明:(1)甘肃省自然资源相对丰富,经济发展的资源基础相对雄厚,但由于对本地资源的过分依赖,加之购买能值投入的严重不足,导致甘肃本地资源得不到有效的利用,农业经济发展程度不高,是一种高资源消耗型经济发展模式;(2)农业生态经济系统的封闭性较强,不符合农业可持续发展的需求.土地生产力水平较低,人均能值用量较低;(3)经济总量还不够大,经济发展中应用的资源能值有很大部分来自本区环境和资源系统而无需付费.农业生态经济系统仍属于资源消耗型,但由于人口众多,入均占有纯能值量较低,且生产和管理过程的科技含量较低,存在着资源的浪费和破坏,系统对干环境的压力较大.因此必须通过增加系统投入,保护环境资源,优化投入结构,调整农业产业结构,依靠科学技术等,以实现甘肃农业可持续发展.     

半干旱岱海西岸地区景观空间异质性分析

本文运用景观生态学原理 ,在不同空间尺度下 ,分析了半干旱岱海西岸地区景观空间异质性 ,认为该地区景观生态空间格局为明显的非随机格局 ;景观格局的异质性一般随尺度的加大而减小 ,景观要素间的差异在不同尺度水平表现不同 ;并且通过对景观要素出现频率直接加以比较 ,确定出不同样线之间差异性的大小。从宏观上为该地区的建设和经济发展提供了科学依据。     

保护艾比湖生态环境的目标与途径的探讨

本文通过对艾比湖生态环境现状的具体分析，从绿洲外环境与绿洲内部环境两个方面对该地环境整治的目标与途径进行了探讨。认为，要保持该地生态环境不再恶化，必须保证该湖５００ｋｍ２左右的水面面积。资料分析表明，近期（公元２０００年）经济开发方案可满足此目标；远景年（公元２０２０年）时，必须考虑跨流域调水方能满足此目标。文章最后还就该地绿洲环境生态建设问题提出了如下意见：１．调整绿洲内部作物结构，扩大苜蓿和枸杞种植面积；２．改造中低产田，提高绿洲生产力，维持其稳定性；３．提高水资源利用率；４．加强农田防护林体系建设，力争早日达到覆盖率为６％的优化目标。     

Changing forests and forest management policy in relation to dealing with forest diseases

ABSTRACT The forest landscape of the United States has changed over time, as has public concern for the trees, water, and wildlife. Early in the history of the United States, forests were viewed as an encumbrance and an inexhaustible resource, used to meet the needs of a growing nation. Around 1900, it became clear that old approaches were not sustainable and forest pathology saw its beginning. Annual lumber production increased from 5.4 billion to 44.5 billion board feet. Forest pathologists were called upon to help manage forests for a variety of products, with a focus on decays of wood and wood products. Projection of timber famine stirred public concern, and a number of laws were enacted to deal with the issue. Pathologists were called upon to deal with many of the issues associated with intensive management, and new pests such as chestnut blight and white pine blister rust demanded attention. Then pathologists were called upon to help manage for multiple benefits, and the issues became more complex. Pests such as mistletoes, root diseases, rusts, nursery pests, and urban pests presented new challenges. Concepts such as landscape level assessments, ecosystem management, and multiple-use led to the management of forests to provide for a complex variety of needs. Management objectives vary across the landscape, and pathologists find themselves working with managers who want to maximize fiber production, those that manage areas set aside for special purposes, and all combinations in between. Issues such as acceptable levels of pests, nonnative invasive species, landowner values, visual and watershed quality, and best management practices must be considered in an ever-changing landscape.