入侵植物对土壤微生物群落的影响研究

外来植物的入侵是全球三大最棘手的环境问题之一,其严重性仅次于栖息地丧失,目前已经成为一个全球性的问题。入侵植物不仅可以导致全球生物多样性的丧失,改变土壤微生物群落的多样性,还能对生态系统造成严重的破坏,带来巨大的经济损失。本文主要研究入侵植物对土壤微生物的群落的影响。     

豚草属植物研究进展

外来物种的入侵已经对我国的农林牧业造成了巨大的经济损失,也严重破坏了生态系统的平衡和物种多样性的保持。作为我国五大入侵植物之一的豚草,更是对人体有严重的致敏作用,在每年的8-9月份能够造成大面积的花粉过敏疾病。它不仅危害人体的健康,对环境和农业生产的危害也非常严重。因此豚草属植物作为外来入侵植物的代表应该更多的被认识其各种特点和习性,以便于进一步防范和治理。本研究对豚草属植物的生物学特性、生态学特性、危害、防治和利用等方面进行了综述。     

中国外来物种入侵达500多种 1年损失570亿元

外来生物的入侵,在严重干扰生态系统的同时,还给我国带来了年均超过570亿元的经济损失。2014年7月29日农业部发布消息称,入侵我国的物种达到529种。其中大面积发生、危害严重的达100多种,对我国生物多样性以及农牧业生产等构成了巨大威胁。农业部农业生态与资源保护总站站长王衍亮介绍,从20世纪80年代以来,外来物种在我国呈现出更快的增长趋势,近10年新增入侵物种近50种,20余种危险性入侵物种接连在我国大面积爆发成灾。外来生物入侵范围也相当广泛,涉及农田、湿地、森林、河流、岛屿、城镇居民     

外来植物空心莲子草入侵人工草坪中种群特征变化研究

外来入侵植物不仅是造成生物多样性下降的主要原因之一,而且也对农田生态系统、渔业生产和景观等造成一定的危害,有些外来入侵植物已经成为一些地区的恶性杂草,空心莲子草就是一个典型的例子。通过对不同栽培年限人工麦冬草坪的取样调查,分析了外来植物空心莲子草种群部分特征在不同入侵阶段中的变化趋势。发现随着入侵时间的延伸,空心莲子草种群密度、个体分枝数量、盖度和植物量都表现出一定的变化规律。这与空心莲子草本身的生物学特征有关,也与人为活动的影响有着密切关系。在某种程度上,人为活动为空心莲子草的扩散创造了一定条件,因此,在人工铲除空心莲子草时特别应避免由于人为活动而造成该植物的扩散。     

辽宁省外来入侵有害生物特征初步分析

通过2006-2008年野外实地调查和文献资料分析,对辽宁省外来有害生物进行总结。结果表明,目前对辽宁省造成危害的外来物种共计116种,分别为外来植物89种、外来害虫17种和外来病原微生物10种,其中危害性较强的主要有14种。这些外来物种的传播和扩散速度较快,传播途径多以无意引入为主,对辽宁省的经济和生态环境危害严重。外来物种入侵地多为生态系统结构单一的农田草场或人工林系统;入侵地多为辽宁省气候温暖湿润的南部,且生物多样性比较丰富的地区。     

金佛山自然保护区外来入侵植物种及其分布情况

生物入侵对全球的生物多样性造成了严重威胁。自然保护区是保护生物多样性的重要基地,因此,自然保护区的生物入侵现状如何备受关注。本研究以金佛山国家一级自然保护区为研究区域,采用样方法和野外踏勘法对金佛山自然保护区的外来植物进行了调查,初步调查结果如下:1)在金佛山共发现56种外来植物种,主要是草本类植物,且多呈零星分布,绝大部分外来植物与本地植物一样仅仅作为一种可利用资源出现,而且没有出现明显的相互竞争,但五节芒具有突出的入侵分布特征;2)56种外来植物中有31种是有意引进的,占入侵种总数的55%;15种是自然入侵的,占27%;有9种是入侵来源不明的,占16%;1种是伴随其他物种无意引进的,占2%。而目前危害面积最大的五节芒就是入侵通道不明的外来植物种;3)调查的样方中外来植物的出现频度与干扰程度相关,干扰越严重的,出现外来植物种的几率越大,踏勘也呈现了同样的规律。     

严防巴西龟对重庆水生生态系统的影响

文章阐述了外来入侵物种巴西龟对重庆本土龟类以及生态环境的影响,提出生物多样性保护对策,旨在为保护本土龟类及水生生态系统提供参考。     

外来生物入侵的途径及预防对策

该文分析了外来入侵生物、对中国造成的经济损失和生态损失,综述了外来入侵生物已经进入中国的种类及入侵途径,据此提出我国需要应对的策略。     

外来生物入侵的途径及预防对策

该文分析了外来入侵生物、对中国造成的经济损失和生态损失,综述了外来入侵生物已经进入中国的种类及入侵途径,据此提出我国需要应对的策略。     

中国草地外来入侵植物现状研究

草地是中国陆地生态系统的重要组成部分,外来入侵植物已对我国草地造成了严重的生态危害和经济损失。了解草地外来植物的种类组成和入侵现状,是加强草地入侵植物管控,开展有效防控措施的基础。本文基于文献报道和数据库资料,系统分析了我国草地外来入侵植物的种类组成、起源、生活型、入侵途径和分布区域。结果表明,我国草地生境现有外来入侵植物183种,隶属41科123属。其中,菊科植物最多,有47种;禾本科和豆科分别有30种、21种。入侵植物来源于美洲的物种最多,共占总数的56.2%;其次是欧洲和亚洲,分别占比23.14%,13.22%。生活型以一年生和多年生草本植物为主;有意引进是最主要的引入途径。我国草地外来入侵植物种类繁多且分布范围广,急需对其开展进一步的调查,全面监测追踪入侵种群动态,积极控制已产生严重危害的植物种类,实行预防在先、防治结合的原则。本文旨在为我国草地外来入侵植物防控工作提供可靠的理论参考。     

蛇岛外来物种入侵现状及生态影响调查

蛇岛是我国唯一一个以蛇岛蝮蛇（Agkistrodon shedaoensis）为主要保护对象的国家级自然保护区,具有重要的科研和生态保护价值,但外来物种入侵已经对该岛生态环境及生物多样性造成严重威胁。本文对蛇岛外来物种的入侵现状进行了野外实地调查,并对其入侵途径、危害特点进行了详细分析。同时,为有效保护蛇岛蝮蛇及蛇岛的生物多样性,提出了控制外来物种入侵的具体建议和对策。     

中国天然草地有毒植物及其放牧家畜中毒病研究进展

中国是世界草地资源大国,天然草地作为我国面积最大的陆地生态系统和重要的绿色生态屏障,具有多种生态功能,同时也是发展草地畜牧业的重要基地和牧民最基本的生产生活资料.但长期以来,人们只重视天然草地的生产功能,而忽视了对天然草地生态系统的保护,使得我国天然草地长期处于过度利用状态,造成草地退化,进一步引发有毒植物等生物灾害多...     

Is Altering Grazing Selectivity of Invasive Forage Species With Patch Burning More Effective Than Herbicide Treatments?

Invasion of rangeland by exotic forage species threatens ecosystem structure and function and can cause catastrophic economic losses. Herbicide treatments often are the focus of management efforts to control invasions. Management with the fire-grazing interaction (or patch burning) might suppress an invasive forage species that has grazing persistence mechanisms developed apart from the fire-grazing interaction. We studied tallgrass prairies invaded by sericea lespedeza (Lespedeza cuneata [Dum.-Cours.] G. Don) to compare rate of invasion between traditional management and management with patch burning, to evaluate the effect of burn season on sericea lespedeza invasion within pastures managed with patch burning, and to correlate canopy cover of sericea lespedeza to canopy cover of other functional groups with and without herbicides. Sericea lespedeza canopy cover increased from 1999 to 2005 in both traditional- and patch-burn pastures, but sericea lespedeza increased from 5% to 16% canopy cover in traditionally managed pastures compared to 3% to 5% in the patch-burn pastures. Rate of increase in canopy cover of sericea lespedeza was less in patches burned in summer (0.41% · year^-1) than in patches burned in spring (0.58% · year^-1) within patch-burn pastures. Most plant functional groups, including forbs, were weak-negatively correlated with canopy cover of sericea lespedeza. Although herbicide application reduced mass of sericea lespedeza, other components of the vegetation changed little. Herbicide treatments temporarily reduced sericea lespedeza but did not predictably increase other plant functional groups. Patch burning reduced the rate of invasion by sericea lespedeza by maintaining young, palatable sericea plants in the burn patch, and could play a vital role in an integrated weed management strategy on rangelands.     

Fuel Reduction,Seeding, and Vegetation in a Juniper Woodland

Western juniper has increased in density and distribution in the interior Pacific Northwest since the late 1800s. Management goals for many juniper woodlands are now focused on reducing tree densities and promoting biodiversity, prompting the use of fuel reduction treatments. Fuel reduction often involves mechanical cutting and disturbances such as slash pile burning and skid trail formation. While these activities may reduce tree densities, the extent to which they will restore native biodiversity and community composition, particularly in woodlands invaded by exotic annual grasses, is unclear. We evaluated the effects of juniper cutting in two experiments of disturbance type (slash piles and skid trails) followed by three native seeding treatments (cultivar, locally sourced, and no seed) on vegetation in central Oregon. Prior to cutting, native perennial grass cover and richness were positively associated and exotic grass cover was negatively associated with juniper basal area. After cutting and 2 yr after seeding, species composition was altered for both disturbance types. Some seeded areas had higher total species richness, higher native species richness, higher cover of seeded species, and higher overall cover compared to areas that were not seeded. But seeding effectiveness in mitigating exotic species spread varied based on exotic species functional group, pretreatment propagule pressure, and experiment disturbance type. Neither seed mix lowered exotic grass cover. There was limited evidence that the cultivar mix outperformed the locally sourced native seed mix. In the short term, fuel reduction activities may have facilitated further conversion of this woodland to an exotic grassland, but longer-term evaluation is needed. In juniper woodlands that have been invaded by exotic species, fuel reduction activities may facilitate further invasion, and exotic species control may be needed to limit invasion and promote native vegetation.     

外来牧草入侵风险评估体系研究

风险评估是预防外来物种入侵的有效手段,为科学评价外来牧草的入侵风险,防止盲目引种带来生态安全威胁,本研究将频度分析法与层次分析法结合,建立外来牧草入侵风险评估指标体系;该体系由5个一级指标和18个二级指标组成,包括外来牧草的入侵性、适应性、扩散性、生物学特性、危害性、防除难度等方面;本研究中,利用4种禾本科外来入侵牧草和3种禾本科外来牧草对构建的评估体系进行验证,并利用该体系对外来牧草柳枝稷（Panicum virgatum L.）进行了入侵风险评估实例研究,得出其入侵风险为中等,主要体现在适应性强和扩散性强方面。本研究建立的评估体系,可初步明确柳枝稷入侵风险的主要来源,为外来牧草的引种管理提供参考。     

Fungal Facilitation in Rangelands: Do Arbuscular Mycorrhizal Fungi Mediate Resilience and Resistance in Sagebrush Steppe?

Arbuscular mycorrhizal fungi (AMF) may exert profound influences on ecosystem resilience and invasion resistance in rangelands. Maintenance of plant community structure through ecological feedback mechanisms such as facilitation of nutrient cycling and uptake by host plants, physical and chemical contributions to soil structural stability, and mediation of plant competition suggest AMF may be important facilitators in stressful arid environments. Plant-AMF interactions could influence succession by increasing native plant community resilience to drought, grazing, and fire and resistance to exotic plant invasion. However, invasive exotic plants may benefit from associations with, as well as alter, native AMF communities. Furthermore, questions remain on the role of AMF in stressful environments, specifically the mycorrhizal dependency of sagebrush (Artemisia spp.) steppe plant species. Here, we review scientific literature relevant to AMF in rangelands, with specific focus on impacts of land management, disturbance, and invasion on AMF communities in sagebrush steppe. We highlight the nature of AMF ecology as it relates to rangelands and discuss the methods used to measure mycorrhizal responsiveness. Our review found compelling evidence that AMF mediation of resilience to disturbance and resistance to invasion varies with plant and fungal community composition, including plant mycorrhizal host status, plant functional guild, and physiological adaptations to disturbance in both plants and fungi. We conclude by outlining a framework to advance knowledge of AMF in rangeland invasion ecology. Understanding the role of AMF in semiarid sagebrush steppe ecosystems will likely require multiple study approaches due to the highly variable nature of plant-AMF interactions, the complex mechanisms of resilience conference, and the unknown thresholds for responses to environmental stressors. This may require shifting away from the plant biomass paradigm of assessing mycorrhizal benefits in order to obtain a more holistic view of plant dependency on AMF, or lack thereof, in sagebrush steppe and other semiarid ecosystems.     

外来植物黄顶菊的入侵机制及生态调控技术研究进展

黄顶菊是近年来入侵我国的一种外来植物,其强大的繁殖能力和入侵性已经对生态环境造成了严重的危害,同时也威胁到农业生态安全。基于此,笔者围绕黄顶菊入侵的生态学机制和生态调控方法等进行了综述。首先,黄顶菊的化感作用和其对不利环境条件的快速适应能力对其入侵扩张具有重要作用;其次,黄顶菊和土壤生态系统之间可能形成“正反馈”作用机制,而这种机制又进一步促进了其成功入侵,其对土壤生态系统包括对养分循环、酶活性和微生物的组成和功能等均产生了深远影响;最后,遵循种群演替的基本规律,可通过建立能与黄顶菊抗衡的本地植被实现生态重建从而达到遏制其扩张,其中选择竞争力强且适合当地气候条件的植物材料至关重要。在此基础上,笔者围绕如何有效控制黄顶菊的危害尚需开展的工作进行了展望,以期为实现对其有效管理和利用提供参考。     

Long-Term Effects of Aeration and Fire on Invasion of Exotic Grasses in Mixed-Brush Plant Communities

Invasion of exotic grasses into grasslands dominated by native plants changes fire cycles and reduces biodiversity. Brush management practices that create soil disturbance, such as aeration, may potentially result in invasion of exotic grasses and replacement of native vegetation. We tested the hypothesis that a long-term effect of aeration and prescribed burning is an increase in exotic grasses. The study was conducted at the Chaparral Wildlife Management Area in the western south Texas plains where four treatments were evaluated: aeration, warm-season burn, aeration followed by a warm-season burn, and no treatment (control). The experimental design was a randomized complete block with four replicates. We estimated percentage canopy cover of exotic grasses, native grasses, forbs, litter, bare ground, and woody and succulent plants in 2007. There was a multivariate main effect among treatments for the dependent variables absolute canopy cover of exotic grasses, native grasses, forbs, litter, and bare ground (Wilks's Lambda F_15,179.84 = 2.78, P = 0.001). Variables that contributed to the significant overall effect included litter (F_3,69 = 4.32, P = 0.008) and native grasses (F_3,69 = 6.11, P = 0.001). The multivariate main effect of treatment was significant (Wilks's Lambda F_9,180.25 = 2.04, P = 0.038) for the relative canopy cover of herbaceous species. Relative cover of exotic grasses was 31% higher (P = 0.024) in control than in the prescribed burn treatment. Native grasses relative cover was 30% higher (P = 0.003) in prescribed burn than in the control treatment. We did not detect differences among treatments in the percentage of total woody and succulent plants canopy cover (P = 0.083). Under the environmental conditions at the time of the study, aeration and/or prescribed burning do not increase exotic grasses.