Molecular tracing of the transmission routes of bois noir in Mediterranean vineyards of Montenegro and experimental evidence for the epidemiological role of Vitex agnus‐castus (Lamiaceae) and associated Hyalesthes obsoletus (Cixiidae)

Epidemiological aspects and transmission routes of bois noir (BN), a grapevine yellows disease induced by ‘Candidatus Phytoplasma solani’, have been exhaustively studied in the affected vineyards of continental Europe but not in the Mediterranean coastal zone. Because ‘Ca. Phytoplasma solani’ and its principal vector Hyalesthes obsoletus presumably originate from the Mediterranean, gaining knowledge of the epidemiological peculiarities of the disease in this area is essential for understanding its global spread and diversification, as well as for designing local management strategies. In this study, molecular epidemiology was applied to trace transmission pathways of ‘Ca. Phytoplasma solani’ in the Mediterranean vineyards of Montenegro, using multilocus sequence typing of tuf, vmp1 and stamp genes of the isolates associated with various hosts. Thus, ‘Ca. Phytoplasma solani’ was tracked from a tentative reservoir plant (inoculum source) through an associated vector population to the infected grapevine. Three pathways of transmission were documented, originating from Urtica dioica, Convolvulus arvensis and Vitex agnus‐castus; however, only the route originating from U. dioica was direct, whereas the latter two were overlapping and could be intermixed. Vitex agnus‐castus is a natural source of ‘Ca. Phytoplasma solani’, representing an important link in disease epidemiology in the Mediterranean and a possible origin of several genotypes occurring in central Europe. Experimental confirmation of the role of Vitex‐associated H. obsoletus in BN transmission in Montenegrin vineyards indicates its tentative role as a vector in the wide area of the Mediterranean, where some of the major wine‐producing regions are located.     

干旱、半干旱区平原水库对坝后盐渍化的影响

为了农业灌溉,干旱、半干旱区修建大量的平原水库,坝基多位于第四纪松散深厚覆盖层上,深厚覆盖层地基上平原水库的渗漏引起坝后地下水位抬升,造成水库下游大面积土地盐渍化,使许多土地减产甚至弃耕。通过对代表性平原水库的监测,分析水库对坝后地下水临界水位的影响程度,进而分析防渗措施的型式。利用有限元计算了深厚覆盖层透水坝基垂直防渗墙和水平铺盖时,坝基渗流量与防渗体尺寸的关系,并联合坝后排水体进行综合控制地下水临界水位,推导出控制地下水临界水位的水库防渗体尺寸计算公式。结合工程实例计算表明,选择合理的防渗体型式并结合排渗体联合控渗,可以从源头上控制坝基的渗漏量,使坝后地下水位控制在临界水位以下,防治坝后土壤的次生盐渍化问题。     

永久性贮水池在水灭火法扑救森林火灾中的运用

本文简要阐述了水灭火法灭火原理与系统组成,提出通过建立永久性贮水池促进水灭火法将成为我国林火扑救重要手段的发展设想。     

Correlates of lake use by breeding common scoters in Scotland

1. Many populations of sea‐ducks, which typically winter at sea but breed on fresh water, are declining. Numbers of common scoters Melanitta nigra (L.) breeding in Scotland halved between 1995 and 2007, despite most breeding sites having special conservation status. To identify potential conservation measures, a 3‐year study was conducted, investigating correlates of lake use by scoters. 2. At 26 scoter breeding lakes, food abundance (macroinvertebrates) and foraging habitats (substrates, water depth) were measured, and their associations with scoter lake use explored using multi‐model inference. Correlates of macroinvertebrate abundance (water quality, fish abundance) were also investigated. 3. Averaged over 3 years (2009–2011), these lakes held 26.7 (SE 6.3) females, around half the Scottish breeding population. Scoters occurred more often at lakes having abundant large‐bodied invertebrates and extensive shallow water. Lakes where the average weight of the largest invertebrate in each sample exceeded 4 mg had 9.2 times (females) or 27 times (broods) more scoter records than other lakes. Lakes where water depths (10 m from the shore) averaged less than 1.3 m had 2.5 times (females) or 12 times (broods) more scoter records than other lakes. 4. The abundance of large‐bodied invertebrates was greater where small fish species (mostly three‐spined sticklebacks Gasterosteus aculeatus) were more common and brown trout Salmo trutta were scarcer. 5. Results suggest two approaches to scoter conservation. At lakes used for hydro‐electricity generation, water level regimes that provide extensive shallow water should be tested to see if these benefit scoters. At lakes used for trout fishing, trout reduction by increased angling should be trialled, to see if this increases large‐invertebrate abundance and scoter use. Copyright © 2015 John Wiley & Sons, Ltd.     

新修坡改梯对土壤水库库容的影响

以重庆缙云山山地黄壤为研究对象,在山地同侧但不同高程的地带,分别选取撂荒地和坡耕地2种土地利用类型地块共6块,对比分析其坡改梯工程前后土壤水库库容变化以及坡改梯区域土壤水库对削洪减灾的作用,并对小流域治理惯用的坡改梯工程的理水功能进行评价。结果表明:(1)坡改梯前后,梯地内土壤水库各项库容变化主要受土层厚度变化影响,但在绝对土层不变的情况下,库容大小在一定程度上受到坡改梯前的土地利用方式影响;(2)土壤水库特性与坡改梯引起的土壤性质变化有关,特别是与土壤孔隙、质地相关指标有关;(3)在百年一遇的设计暴雨条件下,用简化的概念型产流模型进行模拟,发现坡改梯能在理论上削减30%以上的径流,对农业区域旱涝灾害防治有重要作用。     

区域土地利用变化与景观格局分异研究

以1975年和2005年的土地利用图为基础图件,以各个县市为研究单位,提取各个县市的土地利用数据,分析三峡库区近30年来土地利用动态度的变化、土地利用程度的变化;然后接合景观生态学的理论,引入了斑块平均面积、景观的多样性与景观破碎度,寻找分异特征。研究表明,三峡库区近30年各类建设用地的变化速度>河流水域的变化速度>林地、草地的变化速度>耕地的变化速度;各县市土地利用程度在增加;各个景观指数的变化在各个地域分布上的变化趋势是不一样的,土地利用对景观格局的影响比较和缓,三峡库区景观的多样性在减少。     

三峡库区不同坡度带土地利用空间格局研究——以重庆开县为例

基于遥感和地理信息系统技术,利用DEM和GRID模型研究了重庆开县土地利用空间分布与坡度之间的关系,分析了研究区不同坡度带的土地利用格局、主要土地利用类型随坡度变化的空间分布以及不同坡度带土地利用类型的多样性特征。研究结果表明,随着坡度的增加,耕地在各坡度带上的主导地位逐渐减弱,林地和草地的地位逐渐增强,土地利用类型的多样性指数逐渐降低。针对研究区土地利用的空间分布现状,提出了该区土地利用结构调整和规划的优化方向。     

大张坨地下储气库地面工程配套技术

通过开展国内外地下储气库的现场调研,对大张坨地下储气库建设和运行管理过程中存在的问题进行了研究。提出了凝析油气田型地下储气库地面工程配套的11项技术方案。阐述了通过实施技术方案取得的10项研究成果,指出地下储气库建设的空白,地下储气库地面工程配套技术可以为类似地下储气库和低压油气藏的开发建设提供工程依据。     

云南云龙水库库区野生有毒种子植物资源调查与分析*

云南云龙水库库区野生有毒种子植物共有103种,隶属于50科82属,占该区全部种子植物种的23.1%;其种数和科数分别占全国有毒植物的7.9%和35.7%。优势科为Asclepiadaceae,Compositae,Ericaceae,Leguminosae,Lolanaceae和Ranunculaceae,优势属为Anemone,Carpesium,Ranunculus和Rhododendron。最主要的生态型是草本。该区有毒种子植物种数在海拔2010m最多,丰富度指数也表明2010m处的有毒种子植物最丰富,但有些有毒种子植物却广泛分布在较宽的海拔范围内。水库完成蓄水后,将有61.17%野生有毒种子植物被永久淹没。该区有毒植物基本属于"有毒类",最主要的毒性部位为全草,但通常仅一个器官的毒性最大。基础教育、及时建立相关法律制度、扩大人工种植面积和加强市场管理应是保护和开发该区野生有毒种子植物资源的有效措施。本研究结果可为库区周边生态环境保护和该区有毒种子植物资源的科学保护和利用提供基本信息。     

三峡库区水环境评价

三峡库区水环境的质量直接影响到当地甚至整个长江流域的水环境质量。通过对库区水环境基本情况的分析,对库区水环境作出评价、探明问题所在,并提出了解决途径和改进建议。