基于多源遥感数据的呼和浩特城市热岛调控优先区识别研究

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...     

独库高速阿尔先沟段雪崩空间分布及因子探测

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。     

长春市土壤侵蚀潜在危险度分级及侵蚀背景的空间分析

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。     

基于GIS和DEM的土地利用空间格局分析——以兰州市为例

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。     

亚洲小车蝗在内蒙古草原宜生区划分研究

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。     

基于GIS的锡尔河中游生态敏感性分析与评价

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。     

伪步甲危害遥感监测及地形分析——以新疆玛纳斯-呼图壁县草场为例

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。     

乌鲁木齐河流域天山云杉林空间分布格局分析——基于GIS技术的应用

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.     

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

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...     

念青唐古拉山西段冰湖时空变化分析

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。     

Characteristics and hazards of different snow avalanche types in a continental snow climate region in the Central Tianshan Mountains

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.     

加拿大一枝黄花的防控措施

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。     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

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.     

Brief Guide for Authors

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     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.