西北旱区主要气候资源的空间变异性研究

西北旱区地处生态脆弱区,为充分利用其气候资源、协调区域生态环境与社会经济发展,开展主要气候资源的空间变异性研究极为重要。文中利用西北旱区191个气象站点的7个主要气象因子,运用经典统计学和地统计学分析方法来研究各气象因子空间变异性特征。结果表明:(1)干燥度的变异系数>1,其余因子变异系数皆∈(0.157,0.712),表明各气象因子在空间上呈现中等或强烈的空间变异特征;(2)各因子的基底效应值均>0.75,说明气象因子主要受到结构性因子的影响,不会轻易改变或在短时期内难以改变;(3)降水量和相对湿度自西北向东南呈现出递增趋势;蒸发量和干燥度则反之。年均温于新疆和陕西南部出现峰值;日照时数和风速整体上自北向南呈递减趋势。文中通过研究西北旱区气候变化的空间变异特征,有利于把握西北旱区的气候变化规律,为西北旱区农牧业发展提供科学依据。     

区域生态退耕对生态系统服务价值的影响——以宁夏盐池为例

生态退耕使我国西北干旱与半干旱生态脆弱区土地结构和功能发生重大变化,对生态系统服务产生深刻影响。本文运用地理信息系统和遥感技术,分析了1990和2005年,盐池县土地利用和土地类型变化的规律;利用修正的中国陆地生态系统服务价值当量因子,计算出两期生态系统服务价值;分析了土地利用和土地类型变化对生态服务价值的影响。结论如下:1)1990-2005年间,研究区耕地、林地、草地面积得到大幅增加,未利用地大幅减少。2)研究区生态服务价值1990年为99064.6万元,2005年为115421.0万元,增加了20.62%。3)导致生态服务价值变化的主要原因是未利用地大幅度减少,相应转化为单位生态系统服务价值较高的林地、草地、耕地等。研究表明,生态退耕促进了区域土地类型结构优化和生态系统服务功能改善,但是将大量未利用地转化为农田和人工林地的长期生态效应还需进一步观察。文中研究对协调类似区域人地关系,改善人类生存环境和生活福祉具有指导价值。     

基于熵权集对分析的西北地区耕地生态安全水平差异比较

耕地生态安全是关系到粮食安全和人类生存发展的重要问题。构建基于PSR模型的耕地生态安全评价指标体系,运用熵权集对分析方法和障碍度模型对西北地区耕地生态安全水平与障碍因子进行差异比较分析。结果表明:(1)2002—2016年西北地区耕地生态安全总体水平不断提高,但安全等级在地区内部差异明显,2002—2008年,新疆、甘肃、宁夏维持"临界安全"等级不变,青海、陕西联系数主值分别为0.2334、0.2019,安全等级上升为"较安全"。2008—2016年,新疆联系数主值由0.0499提升为0.2692,安全等级上升为"较安全";甘肃、宁夏维持"临界安全"等级;青海、陕西维持"较安全"等级;(2)西北地区压力和响应障碍度均值由2002年的52.434、26.270下降为2016年的38.479、17.353,状态障碍度均值则由21.296上升为44.168。要素层2002年和2016年障碍度均值分别为45.457、32.732、21.811,影响西北耕地生态安全水平障碍因子排序依次为压力、状态、响应。2002年西北地区耕地生态安全水平与压力、状态、响应障碍度的相关系数分别为-0.226、0.120、0.055;2016年分别为-0.830、0.851、-0.661。新疆、青海和陕西出现的耕地生态安全等级提升与状态障碍度大幅度增加有关;(3)新疆和青海耕地生态安全值上升源于人均水资源量的增加;陕西耕地生态安全值上升得益于耕地生产率的提高和耕地环境的改善,但城市建成区的扩张和水资源的短缺制约了生态安全等级提升;甘肃、宁夏耕地生态安全维持等级不变,主要受制于耕地数量的减少和耕地质量的下降等因素。针对西北各地区耕地生态安全提出升级建议。     

近20a叶尔羌河流域生态服务价值对土地利用/覆被变化的响应

为探究综合治理项目实施前后叶尔羌河流域生态与环境变化,基于叶尔羌河流域1990、2000、2010年土地利用遥感解译数据,选取符合干旱区特点的Constanza价值系数,并根据研究区实际情况进行修正计算,对比分析了1990—2010年土地利用/覆盖及生态服务价值的动态变化特征。结果表明:1 1990—2010年,叶尔羌河流域土地利用/覆被变化总体速度为9.12%,变化较强烈;2000—2010年变化速度(6.69%)较1990—2000年(15.76%)缓慢。2 20 a内耕地、建设用地和水域面积分别增加了35.58%、28.21%和10.39%,林地和草地分别减少了11.36%和9.91%,未利用土地面积变化不明显。综合治理项目实施后,研究区植被退化、土地沙化、盐渍化等生态问题仍然存在且有发展。3 1990、2000年和2010年研究区生态服务价值分为330.32×108元、323.62×108元和309.41×108元,生态服务价值总量呈减少趋势,且减少的速率加快。林地和草地面积的减少是生态服务价值总量减少的主要原因。经敏感性分析验证,估算结果对生态服务价值系数的变化缺乏弹性,因此结果是可信的,修正后的价值系数适用于研究区。     

渭干河—库车河三角洲生态系统服务功能及敏感性分析

本研究利用渭干河-库车河三角洲绿洲1989年、2001年和2007年的遥感影像数据,分析了1989～2007年间研究区生态系统服务功能价值变化和生态系统敏感性.结果发现:在整个研究期内,研究区生态系统服务总价值呈下降趋势,从1989年的115.49×108元,分别下降为2001年的106.83×108元和2007年的94.47×108元;在生态系统各单项服务功能价值中,各单项服务功能差异显著,生态服务功能总体呈下降趋势.18 a来,水源涵养功能缺失最为明显,服务价值减少了4.64×108元,而食物生产功能变化最小,其价值增长仅为0.60×108元;同时,通过各单项服务功能在各研究阶段的价值变化情况来看,食物生产功能的生态服务价值增幅明显,水源涵养功能价值下降显著,而娱乐文化功能的价值变化最小;通过对生态系统敏感性指数分析,发现各景观生态系统敏感性指数都小于1,说明研究区生态系统服务总价值对生态价值系数是不敏感的,缺乏弹性.     

宁夏水土保持生态补偿优先区识别

水土保持服务功能下的生态补偿优先区识别的研究，对建立适宜当地生态发展的水土保持生态补偿体系具有重要参考意义。以宁夏为研究区，运用InVEST模型评估水源涵养、土壤保持和碳储存三项主要水土保持服务功能，并进行价值化表达；综合考虑各区县生态补偿优先级和生态脆弱性指数，对全区水土保持生态补偿优先区进行空间识别。研究表明：2000年、2010年、2020年宁夏水土保持价值分别为2478.9×10⁸元、2661.7×10⁸元、2958.5×10⁸元，总体呈现不断增长趋势；在空间上呈现南高北低的空间分布特征，其最高值位于泾源县，最低值位于金凤区；全区20 a来水土保持优先补偿区动态变化差异较小，补偿优先区主要位于生态价值高、经济落后的南部地区，而生态补偿次级优先区则位于中部和北部生态价值较低、经济水平较高区域。对生态补偿优先区进行补偿能够有效提高生态补偿的效率，促进区域生态环境和经济社会可持续发展。     

西北五省温室气体排放核算及动态研究

在IPCC和中国《省级温室气体编制指南》的基础上,计算了新疆、甘肃、宁夏、陕西和青海五省温室气体排放清单。结果表明:2000-2012西北五省温室气体排放总量呈现快速增长趋势,且CO2的排放量最多,其次是CH4和N2O,能源消费产生的温室气体排放是温室气体排放总量中最主要的,而煤炭的消费又是能源消费中最核心的;万元GDP温室气体排放量均呈现下降趋势,说明能源利用效率在不断提高;人均温室气体、单位面积温室气体均快速增长,2012年人均温室气体排放量最多的是宁夏,其次是青海,新疆、陕西和甘肃;单位面积温室气体也是宁夏最高,其次为陕西、甘肃、新疆和青海,均高于应对全球气候目标的人均、单位面积温室气体排放量。因此,西北五省将面临严峻的节能减排任务。     

西北地区秋季干旱指数的变化特征

利用甘肃、宁夏、青海、新疆4省(区)的137个气象站30年的降水、蒸发资料,确定适合西北地区的干旱指数计算方法,分析中国西北地区秋季降水、蒸发、干旱指数的空间分布、时间演变等特征.结果表明:西北地区秋季平均自然降水从东南到西北依次减少,在甘肃西部、青海西北部、新疆南部有一条东西向的少雨带,是干旱最严重的地方.新疆南部、甘肃西部、青海西部重旱频率最高,平均2年一遇;新疆北部、甘肃南部、青海南部、中旱频率为30%左右,平均3年一遇,轻旱频率30%左右,平均3年一遇.表明西北地区的干旱有明显的地域特征,即新疆中南部、甘肃西部、青海西部为干旱区,新疆北部、甘肃中东部、青海东部和南部为半干旱区.     

青海生态系统服务功能价值量评价

生态系统服务功能是指生态系统与生态过程所形成及维持的人类赖以生存的自然环境条件与效用,对人类具有很大的价值,尤其是在生态脆弱的西部地区,生态环境是影响和制约区域经济可持续发展的关键因素。通过采取不同的评估方法对青海省生态系统服务功能价值量分别进行了整体和分项评估,结果表明:整体评估方法得出青海生态价值量约为15428.7亿元/年,分项评估方法得出青海生态价值量约为13849.8亿元/年,但通过多种因素的权衡,最终采用分项评估法得出的青海生态价值量。科学合理的评价青海生态系统服务价值量,能够进一步处理好区域经济发展与生态保护问题,对更好地发挥生态系统的服务功能并使其更好地、持续地为人类服务具有重要意义。     

产业碳排放与影响因素的关联度——基于西北5省面板数据的实证分析

运用西北5省1999-2010年的面板数据,计算产业碳排放量,采用灰色关联度模型,分析影响因素与产业碳排放量之间的关联程度。结果显示：① 从总量来看,1999-2010年西北5省产业碳排放量呈现波动增加的趋势,陕西、甘肃、青海、宁夏和新疆的碳排放量分别从1999年的3.22×107 t、3.05×107 t、7.80×106 t、1.12×107 t和3.02×107 t增加到2010年的1.24×108 t、6.86×107 t、 2.15×107 t、5.76×107 t和9.29×107 t,从2008年起,陕西省的碳排放量开始高于全国平均值。从人均碳排放量来看,也呈现出波动增加趋势,宁夏的人均碳排放量在不同年份均高于其他4省。② 从空间来看,西北5省之间的产业碳排放量存在内部差异,其排序为：陕西＞新疆＞甘肃＞宁夏＞青海。③ 西北5省产业碳排放量与影响因素之间的关联度有某种相似之处,共同表现出：经济效应＞人口效应＞结构效应＞技术效应。④ 不同影响因素对产业碳排放量的关联度存在省际之间的差异,人口效应表现为：宁夏＞甘肃＞新疆＞青海＞陕西,经济效应表现为：新疆＞宁夏＞青海＞陕西＞甘肃,结构效应表现为：甘肃＞宁夏＞青海＞新疆＞陕西,技术效应表现为：宁夏＞青海＞新疆＞陕西＞甘肃。     

Dermestid beetles in ‘evolution Canyon’, lower Nahal Oren, Mt. Carmel, including new records for Israel

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.     

Epidemiology of Toxigenic Fungi and their Associated Mycotoxins for Some Mediterranean Crops

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.     

A survey of the genera of<Emphasis Type="Italic">Microgaster</Emphasis> latreille and<Emphasis Type="Italic">Hygroplitis</Emphasis> thomson (Hymenoptera: Braconidae: Microgastrinae) from China

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.     

Broad bean mottle virus in Morocco; curculionid vectors,and natural occurrence in food legumes other than faba bean (Vicia faba)

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.     

Plant Viruses Transmitted by Whiteflies

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.     

Characterization of potato potyvirus Y (PVY) isolates from seed potato batches. Situation of the NTN, Wilga and Z isolates

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 PVY^N strain and six to the PVY^O strain. No PVY^C was found. Two other isolates reacted serologically like PVY^O, but were unable to elicit a hypersensitive response from the Ny_tbr gene and probably represent the PVY^Z group. At the molecular level, these two isolates showed a combination of both PVY^O and PVY^N and could be recombinants of these strains. Another isolate reacted serologically like PVY^O, but induced vein necrosis in tobacco, like PVY^N-Wilga. Some PVY^N isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVY^NTN group. The PVY^NTN, PVY^N-Wilga and PVY^Z groups probably represent pathotypes within strains PVY^N and PVY^O, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.     

The autumn leafroller: Phenology,damage and parasitoids in a Dutch apple orchard

The phenology of the autumn leafroller,Syndemis musculana, a local pest of apple, was studied in order to forecast larval emergence. From 1983–1986, peak flight as determined with sexpheromone traps was always between 13–18 May. The duration of embryonic development was determined at various constant temperatures and used to estimate the periods of egg hatch in these four years. Each year, most eggs should have hatched in the second decade of June.Differences in attack rates between apple cultivars seem to be explained largely by the variation in picking time. Larvae are only half grown at the beginning of harvest (cv. James Grieve), and have gone into hibernation when the latest variety (cv. Golden Delicious) is picked. Moreover, the varieties Cox's Orange Pippin and Belle de Boskoop, picked about half time, are liable to receive additional damage by caterpillars brought with the picked fruits into storage.Various hymenopterous parasites were reared from caterpillars. As the only leafroller in the orchard which hibernates as mature larva,S. musculana may promote winter survival of some parasitoids, like the eulophidColpyclypeus florus.Samenvatting De fenologie van de herfstbladroller (Syndemis musculana Hübner), een incidentele plaag op appel, werd nader bepaald met het doel het uitkomen van de eieren te kunnen voorspellen. In 1983–1986 viel de piekvlucht, bepaald met behulp van feromoonvallen, steeds tussen 13 en 18 mei.De ontwikkelingsduur van de eieren bij verschillende constante temperaturen werd gebruikt om de periode van uitkomen te schatten. De meeste eieren zullen ieder jaar in de eerste helft van juni uitkomen.Geconstateerde verschillen in schade tussen appelrassen blijken goeddeels terug te voeren op verschillen in pluktijdstip. De rupsen van de herfstbladroller zijn pas half-was als de eerste appels eind augustus geplukt worden, terwijl tegen het einde van de oogst begin oktober de meeste al in winterslaap zijn. Met name tussentijdse rassen, als Cox's Orange Pippin and Schone van Boskoop, lopen extra schade op doordat grotere rupsen met de geplukte vruchten in de kist terecht komen.Uit de rupsen werden negen, al van andere boomgaardbladrollers bekende, sluipwespen gekweekt, Omdat deze bladrollersoort, als enige in de boomgaard, als volgroeide rups overwintert, lijkt zij bij uitstek geschikt als winterwaard.This study was carried out at the Experimental Orchard De Schuilenburg, Schuilenburg 3, 4041 BK Kesteren, the Netherlands, to which address correspondence should be addressed.     

Diagnostics,genetic diversity and pathogenic variation of ascochyta blight of cool season food and feed legumes

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.     

Characterization of Sclerotinia minor populations in Texas peanut fields

In the summer of 2004 an epidemic of sclerotinia blight of peanut, a disease caused by Sclerotinia minor, occurred in Texas in fields where the disease was never previously detected. The disease was observed on many plants within one of the fields (>3000 disease foci), although most foci were <1 m. It is hypothesized that these observations were inconsistent with the recent introduction of a monocyclic pathogen, even if disease developed under conducive environmental conditions. The pattern of disease is most suggestive of the presence of foliar (ascospore) infections, although air temperature was above the known limits for apothecia development if the pathogen had arrived in the field in 2004 peanut seed. To further examine this epidemic, 232 isolates were collected, across a variety of spatial scales spanning this field and other Texas peanut fields, and evaluated for aggressiveness, fungicide sensitivity and genotypic diversity. There was wide variation among isolates for the phenotypic characteristics measured, but there was no evidence that a genotypically unique, highly aggressive, and fungicide resistant isolate had been introduced or evolved. The predominant genotype, TX1, which contained 154 isolates, was found in every county and field population.     

Eyespot of Cereals Revisited: ITS phylogeny Reveals New Species Relationships

Four species so far classified in Pseudocercosporella or Ramulispora (hyphomycetes) are associated with eyespot disease symptoms of cereals. Two of these have been linked to teleomorphs that were described in Tapesia. Sequence data derived from the Internal Transcribed Spacer region (ITS1, 5.8S and ITS2) of the rDNA operon showed, however, that the eyespot fungi associated with Tapesia are not congeneric with Ramulispora sorghi, the type of Ramulispora. The genus name Tapesia is now rejected in favour of the conserved name Mollisia, which appears to comprise heterogeneous fungi. Tapesia yallundae is not closely related to the type of Mollisia, M. cinerea, but clusters separately, being more closely allied to species with Cadophora anamorphs. A new holomorph genus, Oculimacula, is therefore proposed for teleomorphs of the eyespot fungi, while the anamorphs are accommodated in Helgardia gen. nov.