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1.
运用气候变率、线性回归、因子相关分析等方法,对1975-2005年陕北农牧交错区降水、温度变化进行分析,得出气候暖干化趋势显著的结论。对土地、水和粮食安全与干旱化相关系数离散程度分析表明:在气候干旱化作用和煤炭资源过量开发影响下,区域生态环境退化严重;以无定河、延河流域为例,发现流域年降水量每增加10%,其径流量增加22.22%,径流深度加深4.47%,年降水量每减少10%,径流量减少15.98%,径流深度减少3.56%的规律;粮食、牧草受暖干化影响,需水胁迫加剧,出现了产量降低,品质下降,草场承载力下降等问题;最后,针对土地、水和粮食安全对干旱化的响应,提出了适应性对策。  相似文献   

2.
青藏高原东北部边坡地带气温变化特征研究   总被引：2，自引：0，他引：2       下载免费PDF全文
利用青藏高原东北部边坡地带12个地面气象站1961～2000年的月平均气温资料,分析了40年来气温变化的特征及趋势.发现,青藏高原东北部边坡地带气温暖突变发生在1987年,从20世纪80年代初开始区域内最低气温明显上升,到90年代出现最高、最低气温同时上升的现象;夏季、秋季和冬季平均气温普遍呈升高趋势,冬季气温在1978年出现暖突变,升温趋势明显要大于其它季节,春季气温上升趋势不明显.最高、最低气温和气温日较差的变化具有明显的季节差异.  相似文献   

3.
为了对青藏高原东北部边坡地带潜在蒸散量和地表湿润度的变化进行研究,利用甘肃省合作市气象站1961～2010年的地面气象观测资料,根据Penman-Monteith模型计算了合作地区草地潜在蒸散量,发现合作地区年潜在蒸散量呈明显上升的趋势,上升趋势为13.0mm/10a;地表湿润度以-0.02/10a的趋势减小,出现了明显的暖干化趋势。温度升高和相对湿度下降是造成合作地区草地潜在蒸散量上升的主要气候影响因子,同时日照时数增加、降水量减少和风速增大对合作地区草地潜在蒸散量上升也有重要影响。  相似文献   

4.
通过对研究区81个气象站1981~2010年的气象资料和收集的草原火灾资料统计分析,得出内蒙古草原区年平均气温呈直线上升趋势,增温率为0.337℃·10a-1;年降水量呈减少趋势,1999年以后年降水量减少40.8mm;多年平均风速呈减小趋势;气候经历了冷干-暖湿-暖干期。受气候暖干化的影响,内蒙古草原植被退化,牧草高度、盖度和地上生物量降低,地面可燃物载量也降低,使草原火灾呈逐年递减趋势。引发草原火灾的火源雷击火和境外火明显减少,机车失火和吸烟引发的火灾仍高居榜首。从地域分布上看,内蒙古东北部草原火灾的次数在减少;西部地区受降水增多和国家实施的生态建设工程的影响,部分地区植被得到恢复,地面可燃物增多,草原火灾呈上升趋势。风速减小,牧草的及时刈割,牧区的科学管理和牧民防火意识的提高,是近几年没有重特大草原火灾发生的主要原因。  相似文献   

5.
通过利用Holdridge可能蒸散率(PER),对玛曲草地1971～2010年的干湿变化特征进行了分析,近40年玛曲草地PER呈明显的上升趋势,上升趋势达0.03/10a,20世纪90年代后,玛曲草地PER持续偏高,并在1993年出现了增大突变,降水量以7.4mm/10a的趋势减少,温度以0.46℃/10a的趋势上升,生物温度以0.25℃/10a的趋势上升,降水量与生物温度呈现出明显反向变化,玛曲草地有从极湿润区向湿润区过渡的趋势,出现了明显的暖干化趋势。主成分分析表明玛曲草地暖干化的主要原因是气温升高,同时日照时数增加、降水量减少、相对湿度下降和风速减小加剧了暖干化的趋势。受气候暖干化和人为因素的影响,玛曲草地出现了明显的退化和沙化,沼泽湿地的面积也呈明显的减少趋势,导致玛曲草地牧草产量下降,涵养水源能力急剧下降和生物多样性锐减。  相似文献   

6.
1960-2009年大连市气候暖干化研究   总被引：2，自引：0，他引：2  
利用大连市1960-2009年气温和降水两个主要气象要素值的基本观测资料,运用线性倾向估计和GIS空间分析方法,探讨了大连气候的年际时空变化,同时利用Mann-Kendall统计检验和Morlet小波分析对其气候的年代际和周期性变化进行了分析。结果表明:近50a来大连市气候暖干化日趋明显,年平均气温以0.28℃/10a的速率显著上升,并且在1991年发生突变进入异常增暖期,空间上增暖趋势大致呈由南向东北逐渐减弱的态势;降水量基本经历了"减少-增加-减少-增加"的变化过程,总体上呈下降趋势,在1972年降水量由偏多向偏少转变,东北和西南地区降幅较大,腹地最小。此外,气候的暖干化趋势对"自然-社会-经济"复合系统造成的影响应引起重视。  相似文献   

7.
1957-2007年额济纳荒漠绿洲暖干化趋势   总被引：2，自引：0，他引：2  
选用1957-2007年额济纳旗气温、降水、相对湿度等资料,使用距平分析、趋势分析、累计距平、滑动t检验、Yamamoto等方法,分析额济纳旗51年来的气温、降水、相对湿度、干燥度等变化趋势以及干燥度的突变特征.结果表明:51年来额济纳旗年、季平均气温均明显上升,年降水量及夏季降水量呈明显下降趋势,干燥度亦呈逐渐下降趋势,气候暖干化趋势明显,干燥度在1989年发生了突变.在西北部分地区出现暖湿化趋势,额济纳旗则呈现明显的暖千化趋势,在气候暖干化趋势下,额济纳旗环境无疑将承受更大压力,在追求经济快速发展的同时,应考虑气候的暖干化趋势,从而制定科学的环境保护政策.  相似文献   

8.
全球气候暖干化对秦岭南北河流径流泥沙的影响研究   总被引：8，自引：12，他引：8  
以秦岭南侧汉江和北侧渭河多年的径流泥沙观测资料，分析了全球气候暖干化对秦岭南北径流泥沙的变化。分析指出在80年代后，由于全球气候变化的影响，秦岭南北河流年均径流量均减少，与1935－1980年相比，汉江河流年均径流量减少1.9%，渭河河流年均径流量减少27.4%；同时汉江河流泥沙含量明显减少，但渭河河流泥沙含量呈增加趋势，是汉江河流泥沙含量133倍，表明了秦岭南北两侧在全球气候暖干化表现出明显的区域响应性。  相似文献   

9.
利用位于青藏高原—黄土高原过渡区内18个气象站1961—2010年的月平均气温、月降水量等地面气象观测资料，采用Holdridge可能蒸散率(PER)计算方法，对区域内近50a（1961—2010年）地表干燥度的变化趋势进行了分析。发现在区域内存在极湿润区、湿润区、亚湿润区和半干旱区四个不同的气候区，PER在空间分布上有明显的自南向北逐渐上升的特点。区域内极湿润区、湿润区、亚湿润区和半干旱区PER的年际变化趋势分别为0.01·10a-1、0.04·10a-1、0.06·10a-1和-0.02·10a-1，从20世纪80～90年代开始，在湿润区、亚湿润区大部分地方出现了明显的暖干化趋势，而在半干旱区有暖湿化的趋势。区域东部PER升高的主要原因是由于降水量的减少和气温上升，区域西部在降水量增加的情况下，PER仍出现上升的趋势，其主要原因是由于气温上升导致蒸散量增加，且蒸散量增加的幅度超过了降水量增加的幅度；而处于半干旱区的青海省循化县，由于可能蒸散量的上升趋势和降水量的增加趋势非常接近，故其变化最小，有暖湿化的趋势。暖干化已经对青藏高原—黄土高原过渡区内的生态环境、水资源和农牧业生产造成了严重影响。  相似文献   

10.
北方农牧交错带干旱灾害及其对暖干气候的响应   总被引：1，自引：0，他引：1  
利用1961 ～2012年气象数据资料,采用线性回归、反距离加权空间插值(IDW)对北方农牧交错带气温、降水气候要素的时间演变特征进行了分析,并在此基础上运用Is指数和Modet小波变换等方法研究该区域的干旱状况.结果显示:近52年来,北方农牧交错带气温增温速率为0.32℃/10a,降水量减少速率为7.35mm/10a,气候暖干化趋势明显;气候暖干化导致该区干旱灾害的发生频率增加、强度加剧;干旱灾害主要存在7a和8a的年际变化周期,1989年以前气候偏湿润,1989年以后干旱严重;干旱灾害发生频率最高的是西北段部分,西北段和东北段偏旱与大旱严重,而华北段重旱严峻.  相似文献   

11.
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   

12.
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   

13.
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   

14.
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   

15.
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   

16.
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   

17.
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   

18.
《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   

19.
Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.  相似文献   

20.
A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVYN strain and six to the PVYO strain. No PVYC was found. Two other isolates reacted serologically like PVYO, but were unable to elicit a hypersensitive response from the Nytbr gene and probably represent the PVYZ group. At the molecular level, these two isolates showed a combination of both PVYO and PVYN and could be recombinants of these strains. Another isolate reacted serologically like PVYO, but induced vein necrosis in tobacco, like PVYN-Wilga. Some PVYN isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVYNTN group. The PVYNTN, PVYN-Wilga and PVYZ groups probably represent pathotypes within strains PVYN and PVYO, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.  相似文献   

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