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1.
伴随着城市化进程中地表不透水面覆盖增加和城市人口密度增大,城市热岛效应也逐渐加剧,对城市生活品质、城市生态服务系统等产生诸多影响。融合多源卫星遥感数据以及基础地理数据,构建基于“高温环境因子-地表覆盖因子-人口密度因子”模型,结合GIS空间叠加的城市热岛调控区识别方法,对呼和浩特市2020年城区热岛调控优先区进行识别与验证,分析城市地块尺度、社区尺度以及街道尺度上城市热岛优先区的合理性与形成因素。结果显示:呼和浩特市城市热岛调控优先区主要分布于以旧城高密度不透水为主的中心城区老商业圈,呈单中心向外逐渐减少趋势;三个识别因子空间分布特征各不相同,其中人口密度因子和高温环境因子与城市热岛调控优先区空间变化较为一致,是城市热岛调控优先区的主要识别因子,也是城市热岛效应最终形成的主要因素;地表覆盖因子呈西聚东散分布状态,人口脆弱因子呈现出中心聚集度大,向城市南部扩散的空间格局,与呼和浩特市城市发展方向一致。研究表明基于多源遥感数据的模型估算与空间叠加方法识别城市热岛调控区理论上是可行的,研究结果可对未来呼和浩特市城市更新中的城市热岛调节、城市生活品质提升具有一定的指导作用,并为城市热灾害风险管...  相似文献   

2.
拟建独库高速公路阿尔先沟段地貌以高山峡谷为主,由于降雪和气候变化,雪崩频发。利用无人机遥感解译与现场调研协同调查的方法识别92个雪崩点,选取高程、坡度、地表切割度、地面粗糙度,积雪期最大积雪深度、最大风速、平均温度和平均降雪量为驱动因子,运用地理探测器分析不同分辨率地形因子与雪崩稳定性的关系。结果表明:本研究区雪崩发育较为活跃,稳定性较差,但较多雪崩释放区、运动区位于山体坡面,堆积区位于远离拟建线路的谷底,对拟建线路影响较小。通过地理探测器分析,坡度、地面粗糙度对雪崩稳定性解释力与分辨率呈正相关,高程、地表切割度呈负相关,交互探测结果均是双因子增强或者非线性增强,且非线性增强比双因子增强更加显著,坡度与其他因子结合对雪崩稳定性影响至关重要。本研究可为雪崩易发性、危险性评价工作提供可靠的数据支撑,为独库高速公路的建设运营提供科学依据。  相似文献   

3.
在ARCGIS 8.3地理信息系统(GIS)支持下,实现了土壤侵蚀潜在危险的分级及其空间分析。首先,采用美国通用土壤侵蚀模型估算土壤侵蚀量,再用土壤年均侵蚀量、土层厚度和土壤容重得到土壤抗蚀年限图,按水利部标准将长春市土壤侵蚀潜在危险度分为五级,并提出了土壤侵蚀潜在危险指数的概念。借助GIS方法,通过分析不同坡度、不同坡向、不同地貌类型以及不同土地利用类型等背景条件下的土壤侵蚀潜在危险度情况,探讨了土壤侵蚀潜在危险度的空间分布特点。  相似文献   

4.
基于GIS和DEM的土地利用空间格局分析——以兰州市为例   总被引:2,自引:0,他引:2  
基于GIS技术和DEM模型,运用景观生态学方法,研究兰州市的土地利用空间格局。结果表明:(1)居民点及工矿用地、交通用地、水域主要分布在较低、较缓的区域,林地和草地主要分布在较高、较陡的区域。(2)1500m高程范围内、2°-6°坡度区域内,兰州市景观类型和多样性最为丰富;1500-2000m范围内、6°-15°坡度区域内破碎化程度最高;3500m范围内、25°坡度范围内优势景观连接性好,整体性强。(3)景观格局指数与高程和坡度有显著的相关性,最高可达到-0.921,说明地形因子对景观格局有一定的贡献作用,其中shannon多样性指数和shannon均匀度指数对坡度有相同的依赖关系。  相似文献   

5.
研究蝗虫发生的影响因子及其成灾机理,是有效预测其发生的前提和基础。本文利用"3S"等技术,根据我国内蒙古草原地区特点,建立了内蒙古草原亚洲小车蝗宜生区(HA)划分标准与方法,综合地理特征和草原类型等影响因子,采用ArcGIS数据统计手段,构建了草原蝗虫宜生指数模型,利用该模型进行了亚洲小车蝗宜生区区域划分。结果表明以栗钙土为主要土壤类型,以大针茅为主的草地类型,地上植物量达150~250 kg/hm~2,海拔高度在1 000~1 100 m之间和坡度为0~10°的条件下,宜生区指数(IH)为5,划分为一级宜生区。各影响因子所占权重为草原类型土壤类型地上植物量海拔高度坡度。此划分方法的研究有助于明确草原蝗虫分布区域和发生动态,明确内蒙古草原亚洲小车蝗宜生区空间分布情况,为草原蝗虫防治提供数据支撑和决策依据。  相似文献   

6.
基于GIS的锡尔河中游生态敏感性分析与评价   总被引:1,自引:0,他引:1  
以锡尔河中游为研究区,选择高程、坡度、坡向、积温、降水、土地覆盖、植被覆盖度、水域缓冲区及土壤9个生态敏感性指标,构建锡尔河中游生态敏感性评价指标体系,结合层次分析法和GIS空间分析,研究锡尔河中游生态敏感性空间分布特征。结果表明:锡尔河中游生态敏感性总体上表现出中部高、四周低的空间分异特点。研究区生态敏感性分为极度敏感、高度敏感、中度敏感、轻度敏感和不敏感5个等级,各敏感区面积占总面积的4. 39%、10. 48%、29. 97%、31. 26%和23. 90%;研究区生态敏感性程度受植被覆盖度及水体因子影响较大,以恰尔达拉水库和锡尔河干流为代表的极度敏感区和高度敏感区生态系统敏感性最高;受气候因素影响显著,积温和降水因子导致生态敏感性程度具有一定方向性;土地覆盖类型和土壤类型的不同,造成锡尔河中游生态敏感性程度各异,生态敏感性较高的地区主要分布在水库和河流及周围地区,土地覆盖类型以农田用地为主,土壤类型以松软潜育土为主;锡尔河中游生态敏感性与高程、坡度因子呈正相关关系,与坡向呈南(坡向)高北(坡向)低的分布规律。综合评价结果以各敏感区面积叠加统计的形式成图,为锡尔河中游生态环境保护及土地开发利用提供参考。  相似文献   

7.
为揭示伪步甲灾害在不同地形梯度上的差异,结合RS与GIS,于2013—2014年对新疆玛纳斯-呼图壁县草场伪步甲灾害发生情况进行了遥感监测,将危害情况分成不同类别,并分别统计2 a间伪步甲危害面积的变化情况。在此基础上,利用数字高程模型(DEM)提取高程、坡度及坡向因子,分别与不同的伪步甲危害类型进行空间叠加统计分析,探讨研究区伪步甲灾害地形梯度特征。结果表明:900~1 200 m高程范围是伪步甲灾害的高发区;伪步甲危害区主要发生在0°~8.8°区间内;坡向梯度上,严重危害区并没有表现出明显的分布规律。  相似文献   

8.
以天山中部乌鲁木齐河流域为研究区,基于研究区DEN数据、二类森林资源调查数据及Landsat数据,运用3S(GIS、RS、GPS)技术,采用分布频率指数、生境综合指数定量分析流域尺度1989 ~2013年云杉林与地形因子(坡度、坡向、海拔)的关系,结果表明:1)云杉林分布面积大小与海拔服从韦伯函数分布,83%的云杉林分布在海拔2000 ~ 2600m,海拔2200~2400m是其最宜分布区;2)云杉林在坡向上的分布受生境综合指数制约,在生境综合指数最优(0.7 ~0.8)的阴坡分布58.93%的云杉林,在西北坡和东北坡分布30.25%云杉林,在生境综合指数最低(0.3 ~0.4)的阳坡则无云杉林分布;3)使用高斯函数可定量刻画云杉林在不同坡度上的分布状况,83%的云杉分布在坡度16°~45°之间,陡坡(26°~ 35°)云杉分布频率最大,达35%;4)云杉林海拔分布下限为1770m.上述研究明确并量化了天山云杉林分布规律及其与环境因子间的关系,为研究区森林调整与经营提供理论依据.  相似文献   

9.
基于RS与GIS的定西市安定区土地利用变化与土壤侵蚀研究   总被引:6,自引:0,他引:6  
利用1993年和2005年两期的遥感影像数据,在GIS软件支持下,计算了定西市安定区的植被覆盖度和土地利用类型;利用栅格数字高程模型DEM,计算安定区的地表坡度,最终对安定区的土壤侵蚀进行分级.定量分析了定西市安定区的土地利用及土壤侵蚀的时空动态特征,研究结果表明:12年来林草地、建设用地、水域面积增加,其中林草地和建...  相似文献   

10.
基于多源、多期遥感影像与DEM提取的冰湖数据,分析了念青唐古拉山西段1991—2017年冰湖不同维度的分布变化,在此基础上研究了冰湖数量、面积变化与气温、降水变化的关系。结果表明:(1)近年来,研究区的冰湖数量与面积均呈上升趋势,冰湖数量增加161个,面积增加1.185 km~2。其中,1991—2006年平稳增长,2006—2017年大幅增长。(2)冰湖面积与数量在中高海拔范围内均呈增长趋势。新增冰湖主要分布在海拔5400~5700 m,冰湖数量占整体数量的72.41%。(3)分布在不同朝向冰湖的增长速率不同。西南向冰湖增长较为迅速,朝北向冰湖增长相对缓慢。(4)气温上升引起的冰川消融是冰湖生长的间接因素,降水是冰湖生长的重要因素。面积小的冰湖对气候的响应更灵敏,变化更显著,面积大的冰湖,变化幅度小,表明冰湖的动态变化与气候变化紧密相关。通过探究念青唐古拉山西段冰湖变化对冰湖溃决灾害的预测具有重要的指示意义。  相似文献   

11.
Snow avalanches are a common natural hazard in many countries with seasonally snow-covered mountains.The avalanche hazard varies with snow avalanche type in different snow climate regions and at different times.The ability to understand the characteristics of avalanche activity and hazards of different snow avalanche types is a prerequisite for improving avalanche disaster management in the mid-altitude region of the Central Tianshan Mountains.In this study,we collected data related to avalanche,snowpack,and meteorology during four snow seasons(from 2015 to 2019),and analysed the characteristics and hazards of different types of avalanches.The snow climate of the mid-altitude region of the Central Tianshan Mountains was examined using a snow climate classification scheme,and the results showed that the mountain range has a continental snow climate.To quantify the hazards of different types of avalanches and describe their situation over time in the continental snow climate region,this study used the avalanche hazard degree to assess the hazards of four types of avalanches,i.e.,full-depth dry snow avalanches,full-depth wet snow avalanches,surface-layer dry snow avalanches,and surface-layer wet snow avalanches.The results indicated that surface-layer dry snow avalanches were characterized by large sizes and high release frequencies,which made them having the highest avalanche hazard degree in the Central Tianshan Mountains with a continental snow climate.The overall avalanche hazard showed a single peak pattern over time during the snow season,and the greatest hazard occurred in the second half of February when the snowpack was deep and the temperature increased.This study can help the disaster and emergency management departments rationally arrange avalanche relief resources and develop avalanche prevention strategies.  相似文献   

12.
加拿大一枝黄花的防控措施   总被引:2,自引:1,他引:1  
周华  张晓民 《江西植保》2009,32(4):189-190,192
自从2004年加拿大一枝黄花首次在南昌城区出现以来,通过人为传播和自身"雪崩式"的繁殖,两年内蔓延到全市大部分县区,而且分布面积广、地点多、危害程度深,严重威胁到了英雄城南昌的自然生态环境和国土安全。本研究在连续5年部署除治加拿大一枝黄花的实际工作基础上,提出了一系列的防控措施,也为其他类似城市提供借鉴和参考。  相似文献   

13.
Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.  相似文献   

14.
Molecular diagnostic techniques have been developed to differentiate the Ascochyta pathogens that infect cool season food and feed legumes, as well as to improve the sensitivity of detecting latent infection in plant tissues. A seed sampling technique was developed to detect a 1% level of infection by Ascochyta rabiei in commercial chickpea seed. The Ascochyta pathogens were shown to be genetically diverse in countries where the pathogen and host have coexisted for a long time. However, where the pathogen was recently introduced, such as A. rabiei to Australia, the level of diversity remained relatively low, even as the pathogen spread to all chickpea-growing areas. Pathogenic variability of A. rabiei and Ascochyta pinodes pathogens in chickpea and field pea respectively, appears to be quantitative, where measures of disease severity were based on aggressiveness (quantitative level of infection) rather than on true qualitative virulence. In contrast, qualitative differences in pathogenicity in lentil and faba bean genotypes indicated the existence of pathotypes of Ascochyta lentis and Ascochyta fabae. Therefore, reports of pathotype discrimination based on quantitative differences in pathogenicity in a set of specific genotypes is questionable for several of the ascochyta-legume pathosystems such as A. rabiei and A. pinodes. This is not surprising since host resistance to these pathogens has been reported to be mainly quantitative, making it difficult for the pathogen to overcome specific resistance genes and form pathotypes. For robust pathogenicity assessment, there needs to be consistency in selection of differential host genotypes, screening conditions and disease evaluation techniques for each of the Ascochyta sp. in legume-growing countries throughout the world. Nevertheless, knowledge of pathotype diversity and aggressiveness within populations is important in the selection of resistant genotypes.  相似文献   

15.
Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.  相似文献   

16.
We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.  相似文献   

17.
The genera ofMicrogaster Latreille 1804 andHygroplitis Thomson 1895 from China are presented systematically in this paper. Thirty-two species ofMicrogaster and three species ofHygroplitis are known in China. Diagnosis, character variation, distribution and host of each species among the two genera are presented, including its host and distribution. Keys to the species ofMicrogaster andHygroplitis are given. http://www.phytoparasitica.org posting Dec. 19, 2006.  相似文献   

18.
Plant Viruses Transmitted by Whiteflies   总被引:18,自引:0,他引:18  
One-hundred and fourteen virus species are transmitted by whiteflies (family Aleyrodidae). Bemisia tabaci transmits 111 of these species while Trialeurodes vaporariorum and T. abutilonia transmit three species each. B. tabaci and T. vaporariorum are present in the European–Mediterranean region, though the former is restricted in its distribution. Of the whitefly-transmitted virus species, 90% belong to the Begomovirus genus, 6% to the Crinivirus genus and the remaining 4% are in the Closterovirus, Ipomovirus or Carlavirus genera. Other named, whitefly-transmitted viruses that have not yet been ranked as species are also documented. The names, abbreviations and synonyms of the whitefly-transmitted viruses are presented in tabulated form together with details of their whitefly vectors, natural hosts and distribution. Entries are also annotated with references. Whitefly-transmitted viruses affecting plants in the European–Mediterranean region have been highlighted in the text.  相似文献   

19.
《干旱区科学》2014,(6):782-782
正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad  相似文献   

20.
Solacol®, a formulation of the antibiotic validamycin, at 0.33% in 2% malt extract agar, reduced the spread of fungi on dilution plates drastically and allowed twice as much incubation time before subculturing; this resulted in an elevated number of species isolated. Using pure cultures of 62 common soil fungi, it was shown that all fast-growing species (exceptPythium ultimum) were efficiently inhibited but not completely suppressed. Inhibition was comparable to that by 0.5% oxgall, though, while this substance completely suppressed several species, Solacol very strongly inhibited onlyGaeumannomyces graminis, Gerlachia nivalis, Harzia acremonioides, Verticillium biguttatum andRhizoctonia solani. In a further experiment each separate constituent of Solacol was tested against 22 fungi at equivalent concentrations. Validamycin strongly inhibitedChaetomium globosum and two Basidiomycetes, though hardly more than the non-ionic detergent which mainly inhibited the other fungi. A few species were, however, more inhibited by Solacol than by the detergent alone. Solacol at 0.33% is a suitable aid in dilution plating of soil fungi, by increasing the number of colonies and species observed.Samenvatting Solacol®, een formulering van het antibioticum validamycine, remde de groei van schimmels in verdunningsplaten met een concentratie van 0.33% in 2% moutagar en maakte het mogelijk de periode tot afenten met een factor 2 te verlengen; daardoor was het aantal geïsoleerde soorten duidelijk toegenomen. Met reincultures van 62 algemene grondschimmelsoorten werd aangetoond, dat alle snelgroeiende soorten (met uitzondering vanPythium ultimum) voldoende geremd, maar niet volkomen onderdrukt werden. Het remmingspercentage was vergelijkbaar met dat van 0.5% ossegal, hoewel dit laatste sommige soorten volkomen onderdrukte; Solacol remde alleenGaeumannomyces graminis, Gerlachia nivalis, Harzia acremonioides, Verticillium biguttatum enRhizoctonia solani zeer sterk. In een volgend experiment werden de componenten van Solacol t.o.v. 22 fungi apart getoetst in concentraties equivalent aan 0.33% Solacol. Validamycine remde alleenChaetomium globosum en twee basidiomyceten behoorlijk, maar nauwelijks meer dan de niet-ionische uitvloeier, die in hoofdzaak de overige remeffecten veroorzaakte. Enkele soorten werden echter door het complete Solacol veel sterker geremd dan door de uitvloeier alleen. Solacol in een verdunning van 0,33% wordt aanbevolen bij verdunningsplaten voor het isoleren van grondschimmels ten einde het aantal kolonies en soorten te verhogen.  相似文献   

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