草地退化对水土流失的影响

植被是土地的保护伞 ,它具有拦截雨滴 ,缓和雨点冲击 ;阻挡水的流动 ,减缓径流的速度 ;固结土壤 ,防风保土 ;增加土壤有机质 ,改善土壤结构等四大功能。植被一旦退化 ,土壤侵蚀便会发生 ,如土地荒漠化、水土流失等。目前全国土地荒漠化面积 2 62 .2万 km2 ,占国土面积2 7.3%。全国水土流失面积为 367万 km2 ,占国土面积 38%。内蒙古水土流失面积为 2 7.1 7万km2 ,占全区土地总面积 2 2 .97% ,占草原面积 2 1 .5 % ;风蚀面积 7636万 hm2 ,占内蒙古土地总面积 65 % ,全区草地风蚀面积 5 949万 hm2 ,占草地总面积 75 .5 %。各种试验表明 ,植被减少是导致土壤侵蚀的重要原因 ,凡是植被盖度和密度小的草地 ,水蚀和风蚀程度最为严重。因此 ,保护草原植被是改善生态环境的根本措施。为此 ,必须确定合理的草地载畜量 ,增加对草原的投入 ,依法管理草原。     

北京山区采石场边坡植被恢复动态研究

以周口店黄院采石场为研究区域,采用空间代替时间的观测方法,研究不同时间梯度植被群落恢复过程和土壤养分异质性变化,以期为矿山废弃地植被恢复和重建提供可借鉴的理论依据。结果表明:随着植被恢复年限的增加,群落物种更替频繁,灌木和乔木物种出现后,群落整体层次性增强;随着演替的正向进行,各时间梯度恢复植被与最终演替物种组成的相似性指数提高;从极度退化生态系统向平衡生态系统演变过程中,草本层和灌木层的丰富度指数R、Simpson多样性指数D、Shannon-Wiener多样性指数H和Pielou均匀度指数J表现出数值先变大后变小的规律,受矿山废弃地困难立地的影响,乔木层物种数量和个体数目增长不明显;ANOVA方差分析和LSD最小显著差异统计方法研究显示,不同演替阶段导致土壤养分(有机质、全氮、速效钾)的差异性显著(P<0.01),除有效磷外,其他养分含量均随植被正向演替而增加。     

藏北高寒植被群落物种多样性与土壤环境因子的关系

用样带法研究了藏北高寒植被群落物种多样件及其与土壤环境因子之间的关系,对3类高寒植被多样性指数和7个土壤指标进行相关性分析和回归分析.结果表明:从高寒草原到高寒荒漠植被,群落组成逐渐趋于简单化;土壤环境因子影响多样件指数,高寒植被土壤有机质、全氮、有效氮、全磷和多样性指数及丰富度指数有极显著(P＜0.01)正关系;均匀...     

沙地生态系统中蚂蚁活动与地表植被及土壤环境间的互作关系

动物扰动与植被和土壤环境的之间互作关系是土壤生态系统的重要一环,对植被结构、动物分布和土壤特性具有重要的调节作用,对沙地生态系统恢复过程具有不可估量的影响。文中根据在科尔沁沙地土壤动物的研究结果,总结了地表植被和土壤条件对蚂蚁活动分布的影响,分析了蚂蚁活动对植被分布、结构和土壤性状的反馈作用,详细地探讨了蚂蚁筑丘活动与...     

潜在和新发外来入侵物种三维可视化预警监测系统构建与应用

潜在和新发外来入侵物种数据可视化展示是外来入侵物种管理的重要载体。潜在和新发外来入侵物种数据具有混合型(包括结构化和非结构化)和离散性(数据分布在不同的系统或平台)特点。本文在分析这些数据的基础上,以预警监测模型分析与三维可视化集成、多源异构数据融合为切入点,综合运用3D GIS、物联网、大数据等技术手段,研发潜在和新发外来入侵物种可视化系统的关键技术;以潜在外来入侵物种地中海实蝇Ceratitis capitata和新发外来入侵物种番茄潜叶蛾Tuta absoluta为例,构建多源异构数据融合的潜在和新发入侵物种预警监测三维可视化系统,形成了基于GIS技术的典型潜在和新发外来入侵物种可视化平台的解决方案。该系统可为我国潜在和新发外来入侵物种分级控制管理和区域性防控预案制定提供科学支撑。     

Burial effects on seed germination and seedling establishment of Prosopis juliflora (SW.) DC

Seed germination and seedling establishment are critical stages in plant life history, and both processes may be affected when buried under soil. Our aim was to investigate the effects of soil burial on the germination and seedling establishment of invasive Prosopis juliflora (Fabaceae). We studied the effects of burial, from soil surface to 4?cm deep, under greenhouse conditions and the effects of seed-storing in burial conditions at two depths (5 and 20?cm) and two storing periods (during 6 and 12?months) in field conditions. Soil burial limited the germination and the establishment of P. juliflora, which did not germinate at soil depths deeper than 3?cm. Some seedlings coming from seeds germinated at 2?cm, and every seedling at the soil surface and at 3?cm deep died. In contrast, survivorship of emerged seedlings was close to 90% between 0.5 and 2?cm depth. Seedlings developed the longest shoots at 1?cm deep, indicating that P. juliflora was able to get advantage at a moderate soil depth. Un-embedded seeds survived buried in the soil for months; however, their germination and the emerged seedling survivorship decreased after burial for 12?months.     

SSR分子标记技术在入侵昆虫学研究中的运用

外来入侵生物通过与本地生物竞争营养、水分和生存空间,造成严重的生态破坏和生物污染,最终导致生物多样性的丧失,逐渐成为人类生存和社会可持续发展的新威胁。简单序列重复(simple sequence repeats,SSRs)或微卫星DNA(microsatellites DNA)分子标记是生物群体遗传结构分析与变异研究中极有价值的分子标记,由于其具有多态性检出率高、信息含量大、共显性标记、实验操作简单、结果稳定可靠等优点,目前在外来入侵生物研究中得到广泛应用。本文概述了SSR分子标记在入侵昆虫来源鉴定、杂交和基因渗透、瓶颈效应等方面的应用进展,并对其在入侵生物学中的应用前景进行了展望。     

利用条形码技术鉴定苹浅褐卷蛾

苹浅褐卷蛾原产澳大利亚,目前仅分布于少数地区,是澳大利亚、新西兰及英国等国家多种经济作物上的重要害虫,苹浅褐卷蛾形态具有多态性,对其形态鉴定一直非常困难,由此也增加了该虫在口岸上的入侵风险。本研究使用DNA条形码技术(barcoding)测定了采集自新西兰5个不同地区苹浅褐卷蛾种群26个样本的细胞色素酶I(COI)序列。研究表明,苹浅褐卷蛾种内COI序列差异远小于3%,而与BOLD数据库中卷蛾科其他种类的种间差异约为7%～16%,远大于3%。该结果肯定了条形码技术能够成为口岸快速、准确鉴定苹浅褐卷蛾的有效方法。     

The influence of water level and nutrient availability on growth and root system development of Myriophyllum aquaticum

Myriophyllum aquaticum is an aquatic plant of still or slow flowing waters. The species mostly occurs in its emerged growth form in dense stands, but submerged shoots can also be found. Due to its rapid growth, M. aquaticum is considered one of the most important aquatic weeds worldwide. In southern Europe, M. aquaticum occurs in irrigation and drainage systems, rice fields and lowland wetlands. In this study, root development and growth response of M. aquaticum to different water levels and nutrient availabilities were investigated in a rhizotron experiment under Central European climatic conditions. The species shows an ability to respond to drained soil conditions by a rapid root growth (up to >1 cm day⁻¹), resulting in a deep root system under drained conditions. In waterlogged soil, the root system spreads more horizontally. Root density increased with increasing nutrient availability. Root:shoot ratio increased significantly with decreasing nutrient availability. In addition, total shoot length, shoot biomass, root biomass and total biomass differed significantly between different water levels and different nutrient availabilities. Relative growth rate increased with increasing water level and nutrient availability. Shoot porosity was higher in nutrient rich substrate than in nutrient low substrate. Root porosity increased with increasing water level. In conclusion, M. aquaticum shows a high tolerance to different water levels, which may be important for future habitat conditions in waterbodies and wetlands in Central Europe under the impact of global change with increased water level fluctuations.     

我国农业入侵生物科学管控体系形成与发展

生物安全是国家安全的重要组成部分, 生物安全研究技术是当前最活跃的技术领域, 是推动世界新一轮科技革命和产业变革的重要力量之一, 日益成为全球科技竞争的热点领域和各国争相布局的战略制高点。进入21世纪以来, 我国农业外来生物入侵等生物安全问题不断凸显, 直接影响粮食安全、生态安全乃至社会与国家安全。本文总结了近年来我国在生物入侵防控领域研究的现状和所取得的成就, 并结合国际生物入侵研究的发展态势及聚焦我国生物入侵领域技术发展的重大需求, 明确我国农业生物入侵防控研究领域的重大科学问题及科技发展方向和重点任务, 进而定位我国在全球生物入侵科技创新坐标系中的位置, 做好我国在该领域的重大科学工程和战略性科学计划, 为我国中长期生物安全科技发展规划和重大任务部署提供重要决策和依据。     

巴彦淖尔市天然草地昆虫多样性及其与植被的相关性分析

为有效防治天然草地的害虫和修复天然草地,采用Z字形扫网取样法对巴彦淖尔市温性荒漠草原、温性草原化荒漠、温性典型草原和温性荒漠4种天然草地类型的昆虫种类和数量、植被种类和植被盖度进行实地调查,对4种草地类型的昆虫群落进行多样性分析和相似性分析,并对昆虫群落多样性与植被因子（植被种类及植被盖度）进行相关性分析。结果显示：自巴彦淖尔市4种天然草原中共采集了2 675头昆虫,隶属8目35科54属69种,其中直翅目昆虫种类最多,是巴彦淖尔市天然草原的优势种;温性荒漠草原昆虫群落的Shannon-Wiener多样性指数和Margalef丰富度指数显著高于其他3种草地类型;4种草地类型昆虫物种的Jaccard相似性系数均小于0.50,表明各草地类型之间昆虫物种的差异较大;植被种类与昆虫群落的Shannon-Wiener多样性指数、Margalef丰富度指数正相关,且植被种类对4种草地类型的贡献率均较高,表明天然草地的植被越丰富,昆虫多样性指数就越高。     

塔里木河下游植被退化区土壤种子库特征

本文在塔里木河下游选择了四个典型荒漠植被退化区,通过土壤种子库萌发实验,对土壤种子库的基本特征以及与地上植被的关系进行了对比研究。结果表明:1)四个植被退化区土壤种子库总共含有10个物种(属),平均密度1633.33粒/m2。2)四个植被退化区种子库密度总和来看,0-5cm层>5-10cm>层10-30cm层,但在各个研究区中种子库密度的垂直分布异质性差异很大,没有一致的规律。3)各个研究区土壤种子库种子的生活型组成,草本物种密度均明显高于灌木。4)土壤种子库与地上植被的相似性系数在四个研究区均很低;随着退化程度的加重,种子库的密度和物种数均呈现明显的下降趋势,但土壤种子库物种组成的稳定性要高于地上植被。     

Influence of edible fruit coatings on Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) oviposition and development

Drosophila suzukii (Matsumura) is a highly invasive vinegar fly recently detected in the United States that severely threatens the viability of soft skinned fruit production. Insecticides mitigate some of this damage, but alternative methods to manage D. suzukii infestation are needed. We tested three edible coatings to determine if they could prevent or reduce oviposition by D. suzukii females or affect immature survivorship and development in two important host crops, blueberry and raspberry. None of the coatings prevented oviposition, but some reduced the number of eggs laid. Two carnauba wax-based coatings, PrimaFresh 45 and Raynox, dramatically reduced survivorship of immature D. suzukii in raspberries, but not in blueberries. Our results suggest that obtaining thorough, even coverage in the field will be essential if edible coatings are to be used as a management strategy for D. suzukii.