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1.
王庆  卢志兴  赵婧文  陈又清 《昆虫学报》2018,61(12):1430-1438
【目的】昆虫之间的互利关系和植物多样性在生态系统中具有重要的作用,本研究旨在探讨蚂蚁-紫胶虫互利关系的下行效应以及寄主植物多样性的上行效应对节肢动物群落各营养级的影响。【方法】试验样地位于云南省普洱市墨江县雅邑乡的人工紫胶林中。通过随机裂区试验方法,于2016年8月和9月分两次用手捡法、网扫法和震落法采集了蚂蚁-紫胶虫3种互利关系处理(有互利关系、无互利关系和自然对照)以及3种植物多样性处理(单一种植、2树种混植和3树种混植,分别代表植物多样性1, 2和3)下样地寄主植物上所有的节肢动物,并按照不同营养级将其分类。【结果】蚂蚁-紫胶虫互利关系会显著降低消费者多度[有互利关系(14.2±0.95)<自然对照(18.57±1.13)<无互利关系(23.27±1.38), (F=4.290, P=0.017)],植物多样性会显著提高消费者多度[植物多样性1(13.49±2.54)<植物多样性2(16.31±2.50)<植物多样性3(25.01±2.47), (F=56.03, P<0.001)];在两者的交互作用下,无论哪个植物多样性水平上,有互利关系处理的消费者多度都显著低于无互利关系处理的消费者多度 (F=6.850, P<0.001)。互利关系对捕食者多度无显著影响(F=1.277, P=0.284),植物多样性会显著增加捕食者多度[植物多样性1 (1.72±0.49) <植物多样性2 (3.42±0.54) <植物多样性3 (3.59±0.55), (F=10.976, P<0.001)],两者的交互作用对捕食者多度无显著影响(F=0.428, P=0.788)。互利关系和植物多样性会显著增加蚂蚁多度[自然对照(44.08±8.94) <有互利关系(324.82±65.35), (F=48.9, P<0.001)], [植物多样性1(86.31±12.51)<植物多样性3 (131.20±18.80) <植物多样性2(151.27±21.68), (F=137.85, P<0.001)], 两者的交互作用也会显著增加蚂蚁多度(F=80.31, P<0.001)。【结论】蚂蚁与紫胶虫的互利关系显著降低植物上的植食性害虫,对捕食者不产生显著作用,但显著提高蚂蚁多度;而植物多样性对节肢动物各营养级都有积极作用;两者会产生一定的联合作用,对各营养级产生不同的影响。  相似文献   

2.
消费者多样性对食物网结构和生态系统功能的影响   总被引:1,自引:0,他引:1  
前所未有的生物多样性丧失使人们越来越关注生物多样性的生态系统功能.现有的绝大多数研究都是局限在单一营养级别上,主要是植物上,但是今天越来越多的证明表明消费者的多样性对生态系统结构和功能具有深刻影响.综述了消费者多样性对相邻或非相邻营养级的种群密度、物种多样性和生产力等方面影响的最新进展,同时也提出了若干研究展望.总体上.消费者多样性,无论是草食动物还是肉食动物,都倾向于增加该消费者所在营养级的养分和能量利用效率,以及生产力.这可能源于取样效应,或者物种之间的互补作用,类似于植物物种多样性影响初级生产力的机制.草食动物可能降低或者提高植物物种多样性,或者没有显著影响,其具体效应取决于生态系统生产力水平和草食动物的大小.捕食者哌能通过直接抑制草食动物而间接提高植物的多样性和生产力,但这种效应的大小差异很大,甚至效应的方向,都可能随团体内捕食者所占的比例而改变.未来的研究,应该考虑应用较大尺度的实验来检测食物网复杂营养关系对生态系统特性的影响,继续探讨消费者对生态系统功能的影响机制.认为异速生长法则和生态化学计量学在食物网组分关系研究中的应用将有利于增强人们对消费者.生态系统功能关系的理解.另外,全球变暖和转基因植物对食物网中消费者结构和生态系统的功能的影响也将是未来的一个重要研究方向.  相似文献   

3.
蚂蚁-紫胶虫兼性互利关系对蚂蚁群落多样性的影响   总被引:4,自引:0,他引:4  
为了探讨蚂蚁-紫胶虫兼性互利关系对树冠上蚂蚁群落多样性的影响,作者于2009年12月至2010年5月,采用目光搜寻的方法调查了不同紫胶虫数量样地(样地Ⅰ有效枝条寄生率为60%、样地Ⅱ为30%、样地Ⅲ为10%、样地Ⅳ不放养紫胶虫)中钝叶黄檀(Dalbergia obtusifolia)树冠蚂蚁群落的多样性.结果显示,兼性互利关系能够显著提高树冠蚂蚁群落多度及物种丰富度,改变树冠上蚂蚁的群落结构;由紫胶虫数量高低导致的蜜露产量的多寡对树冠上蚂蚁的多度和群落结构均具有显著影响,但对物种丰富度无显著影响;同时紫胶虫的个体发育阶段也是影响树冠上蚂蚁多度的重要因素.本研究证明,紫胶虫对于提高树冠上蚂蚁的多样性具有显著的正面影响,紫胶林对蚂蚁多样性保护有利.  相似文献   

4.
张霜  张育新  马克明 《植物生态学报》2010,34(11):1344-1353
蚂蚁-植物互利关系是生态和进化研究中的模式系统之一。该文分析总结了近年来有关蚂蚁对植物的保护作用及其调节机制的研究进展。植物通过给蚂蚁提供食物体、蚁菌穴和蜜露吸引蚂蚁, 通过自身的物理、化学方式调节与蚂蚁的互利关系, 使蚂蚁能有效地保护自已, 防止欺骗和寄生的发生。反过来, 蚂蚁可以减少植食性动物对植物的伤害和取食, 减少叶片损伤, 提高种子产量和质量, 提高植物的竞争优势等。虽然蚂蚁对植物的保护作用的强度受到多种生物与非生物因素的影响, 变异性较大, 但在大多数情况下, 蚂蚁-植物之间仍呈显著的正相互作用。同时, 蚂蚁-植物的相互作用还具有广泛的生态影响, 尤其会大大降低林冠上节肢动物群落的物种多样性和多度。未来的研究需要加强蚂蚁-植物互利关系的起源与维持机制、对蚂蚁自身的影响、与生物入侵的关系, 以及进化生态学等方面的研究。  相似文献   

5.
土地利用方式的转换对农业生态系统中节肢动物不同功能群之间的相互作用关系有显著的影响.本研究通过调查不同经营方式的紫胶林中蚂蚁Formicidae和紫胶虫寄生蜂的多样性情况,探究紫胶生产系统对这两种功能群之间相互关系的影响路径和强度.于2018年4-9月,在临沧市云县两块不同的紫胶林样地中放置了树栖陷阱和地表陷阱用于收集蚂蚁,并用套笼法收集紫胶虫Kerria spp.的寄生蜂.结果表明:有地表覆盖的紫胶林样地(X2)中地表蚂蚁的多度显著高于无地表覆盖样地(X1)(F=7.256,P=0.011),而X2样地紫胶虫寄生蜂的物种丰富度(F=20.250,P=0.003)和多度(F=17.108,P=0.003)却显著低于X1样地.地表覆盖对树栖蚂蚁(β=0.787,P<0.001)和地表蚂蚁(β=0.652,P=0.004)均有显著的积极影响,而地表覆盖(β=-0.932,P<0.001)及地表蚂蚁(β=-0.362,P=0.039)对寄生蜂多度有显著的负面影响.本研究揭示了紫胶生产系统中,地表覆盖有利于维系蚂蚁-紫胶虫互利关系,抑制紫胶虫寄生蜂,从而对紫胶生产产生积极作用.  相似文献   

6.
作物多样性对害虫及其天敌多样性的级联效应   总被引:1,自引:0,他引:1  
植物物种丰富度对植食性、寄生性和捕食性节肢动物多样性的影响是群落生态学的一个重要研究内容.探讨了作物物种丰富度对害虫及其天敌多样性的影响.通过连续4年5个作物物种丰富度水平的野外实验,发现作物物种丰富度显著性影响害虫物种丰富度,但对天敌物种丰富度的影响甚微.然而,害虫物种丰富度却显著影响天敌物种丰富度.这些发现表明,相邻营养层之间的级联效应较强,而不相邻营养层之间的作用关系被中间营养层所弱化.此外,本研究还发现,混栽田中节肢动物群落稳定性高于单一种植田中节肢动物群落稳定性.本研究结果突出了不同营养层之间复杂的作用关系以及作物多样性在农业生态系统食物网中的关键性角色.  相似文献   

7.
王晴晴  高燕  王嵘 《植物生态学报》2021,45(10):1064-1074
食物网主要依靠基于不同营养级间物种互作形成的上行与下行调控维持其结构。全球变化能够改变种间关系, 威胁生物多样性的维持, 然而目前对全球变化改变食物网结构的机制仍处于探索阶段。近年来通过大时空格局与多营养级食物网研究, 发现全球变化的作用机制主要可归结为3种: 物候错配、关键种丧失与生物入侵。该文聚焦于这3种机制, 综述各种机制造成的食物网结构变化并探讨相关的进化与生态驱动因素。三种干扰机制均通过改变原有种间关系, 影响食物网调控, 改变食物网结构。不同的是, 物候错配造成的种间关系变化是由于不同物种的物候对全球变化产生非同步响应所致; 关键种丧失则使营养级间取食/捕食关系发生变化甚至缺失; 而入侵物种通过竞争排除同营养级物种改变种间关系。最后, 该文提出食物网结构变化的实质是物种是否能够适应快速变化的生态环境, 并据此展望未来研究方向。随着全球变化影响日益加剧, 急需继续深入探索导致全球变化下食物网结构改变的机制, 为制定合理的生物多样性保护与生态修复规划提供重要理论支撑。  相似文献   

8.
揭示植物群落对土壤动物和微生物多样性的上行调控效应有助于理解不同营养级生物多样性的维持机制。以往的研究主要集中在植物物种多样性对土壤动物和微生物多样性的影响,而关于植被功能组成自下而上的影响研究较少。以上海大金山岛13个植物群落为对象,在分析落叶木本植物占比与树木和草本物种多样性,以及土壤动物和细菌多样性的关系基础上,利用结构方程模型区分了落叶木本植物占比对土壤动物和细菌多样性的直接与间接影响效应。结果显示:落叶木本植物占比不仅分别对草本物种多样性和土壤动物多样性分别产生直接正效应和负效应(P<0.01;P<0.05),也会通过草本物种的级联效应间接的降低地下土壤细菌多样性(P<0.10)。然而,木本植物多样性仅与草本物种多样性显著正关联(P<0.10),与土壤动物和细菌多样性无显著关联(P>0.10)。该研究结果表明,相较于木本植物多样性,落叶植物占比在中亚热带北缘森林生态系统不同营养级生物多样性维持格局中扮演着更为重要的角色。  相似文献   

9.
生态系统中的物质和能量主要沿食物链在食物网中流通,诸多研究表明入侵植物对生态系统功能的影响是通过改变当地原有的食物网结构而实现的,因此外来植物入侵对食物网的影响受到人们越来越多的关注.本文分析了植物入侵引起食物网变化的原因以及改变食物网的途径,探讨了土著食物网特点对群落可入侵性的影响,得出以下结论:(1)食物网的变化主要是由于入侵植物引起的消费者基础食物资源或者周围环境条件的变化造成的;(2)入侵植物通过3种途径影响食物网:一是入侵植物具有较好的可利用性,能够直接被土著草食者取食,通过上行效应按照原有的路径进入土著食物网;二是当入侵植物的可利用性较差时,入侵植物所固定的能量通过引入新的消费者或者转变流通路径形成新的食物网结构;三是入侵植物通过非营养作用造成食物网中各级消费者的种群密度和行为活动等发生变化,进而影响土著生物群落和食物网结构;(3)食物网的大小及其连通性可能影响外来植物的入侵成功率.在今后的研究中,为深入揭示生物入侵对食物网的影响,在短期控制实验的基础上应加强长时间尺度的动态研究,对于食物网变化的定量描述对象也需要进一步加以明确.此外,食物网对入侵植物生态修复的响应以及食物网变化对入侵植物的反馈作用等也具有重要的研究价值.  相似文献   

10.
蚂蚁光顾云南紫胶虫对其天敌紫胶黑虫种群的影响   总被引:2,自引:0,他引:2  
为了弄清蚂蚁光顾云南紫胶虫Kerria yunnanensis Ouet Hong对其天敌紫胶黑虫Holcocera pulverea Meyr种群的影响,于云南紫胶虫成虫期,对有无蚂蚁光顾的胶被抽样,调查胶被上紫胶黑虫的为害率及种群数量变化。结果显示,紫胶黑虫对有无蚂蚁光顾的胶被的为害率均很高,并逐月增加;其中有蚂蚁光顾的胶被紫胶黑虫的为害率略小于无蚂蚁光顾的胶被。蚂蚁光顾能明显减少紫胶黑虫的种群数量(︱t︱=2.764,df=356,P<0.01),其原因可能是蚂蚁光顾能干扰紫胶黑虫的产卵行为、破坏卵、取食卵和幼虫并且这种保护主要发生在云南紫胶虫幼虫期;云南紫胶虫进入成虫期后,由于紫胶黑虫生活于胶被内,并且产卵于胶被的凹陷处或雄虫胶壳内或雌虫肛突孔处,蚂蚁很少与紫胶黑虫相遇,故蚂蚁光顾对紫胶黑虫每月增长量没有显著影响(︱t︱=0.970,df=161,P>0.05)。紫胶黑虫和蚂蚁相遇的行为反应存在显著差异(χ2=4.781,df=1,P<0.05),蚂蚁对紫胶黑虫有捕食作用。蚂蚁与云南紫胶虫之间存在互利关系。蚂蚁取食云南紫胶虫的蜜露,能降低紫胶黑虫的为害率,并减少紫胶黑虫的种群数量,从而保护云南紫胶虫。  相似文献   

11.
We tested integrative bottom-up and top-down trophic cascade hypotheses with manipulative experiments in a tropical wet forest, using the ant-plant Piper cenocladum and its associated arthropod community. We examined enhanced nutrients and light along with predator and herbivore exclusions as sources of variation in the relative biomass of plants, their herbivores (via rates of herbivory), and resident predaceous ants. The combined manipulations of secondary consumers, primary consumers, and plant resources allowed us to examine some of the direct and indirect effects on each trophic level and to determine the relative contributions of bottom-up and top-down cascades to the structure of the community. We found that enhanced plant resources (nutrients and light) had direct positive effects on plant biomass. However, we found no evidence of indirect (cascading through the herbivores) effects of plant biomass on predators or top predators. In contrast, ants had indirect effects on plant biomass by decreasing herbivory on the plants. This top-down cascade occurred whether or not plant resources were enriched, conditions which are expected to modify top-down forces. Received: 9 August 1998 / Accepted: 1 December 1998  相似文献   

12.
Apex predators and plant resources are both critical for maintaining diversity in biotic communities, but the indirect (‘cascading’) effects of top‐down and bottom‐up forces on diversity at different trophic levels are not well resolved in terrestrial systems. Manipulations of predators or resources can cause direct changes of diversity at one trophic level, which in turn can affect diversity at other trophic levels. The indirect diversity effects of resource and consumer variation should be strongest in aquatic systems, moderate in terrestrial systems, and weakest in decomposer food webs. We measured effects of top predators and plant resources on the diversity of endophytic animals in an understorey shrub Piper cenocladum (Piperaceae). Predators and resource availability had significant direct and indirect effects on the diversity of the endophytic animal community, but the effects were not interactive, nor were they consistent between living vs. detrital food webs. The addition of fourth trophic level beetle predators increased diversity of consumers supported by living plant tissue, whereas balanced plant resources (light and nutrients) increased the diversity of primary through tertiary consumers in the detrital resources food web. These results support the hypotheses that top‐down and bottom‐up diversity cascades occur in terrestrial systems, and that diversity is affected by different factors in living vs. detrital food webs.  相似文献   

13.
1. Intraguild predation occurs when top predators feed upon both intermediate predators and herbivores. Intraguild predators may thus have little net impact on herbivore abundance. Variation among communities in the strength of trophic cascades (the indirect effects of predators on plants) may be due to differing frequencies of intraguild predation. Less is known about the influence of variation within communities in predator-predator interactions upon trophic cascade strength. 2. We compared the effects of a single predator community between two sympatric plants and two herbivore guilds. We excluded insectivorous birds with cages from ponderosa pine Pinus ponderosa trees parasitized by dwarf mistletoe Arceuthobium vaginatum. For 3 years we monitored caged and control trees for predatory arthropods that moved between the two plants, foliage-feeding caterpillars and sap-feeding hemipterans that were host-specific, and plant damage and growth. 3. Excluding birds increased the abundance of ant-tended aphids on pine and resulted in an 11% reduction in pine woody growth. Mutualist ants protected pine-feeding aphids from predatory arthropods, allowing aphid populations to burgeon in cages even though predatory arthropods also increased in cages. By protecting pine-feeding aphids from predatory arthropods but not birds, mutualist ants created a three-tiered linear food chain where bird effects cascaded to pine growth via aphids. 4. In contrast to the results for tended aphids on pine, bird exclusion had no net effects on untended pine herbivores, the proportion of pine foliage damaged by pine-feeding caterpillars, or the proportion of mistletoe plants damaged by mistletoe-feeding caterpillars. These results suggest that arthropod predators, which were more abundant in cages as compared with control trees, compensated for bird predation of untended pine and mistletoe herbivores. 5. These contrasting effects of bird exclusion support food web theory: where birds were connected to pine by a linear food chain, a trophic cascade occurred. Where birds fed as intraguild predators, the reticulate food webs linking birds to pine and mistletoe resulted in no net effects on herbivores or plant biomass. Our study shows that this variation in food web structure occurred between sympatric plants and within plants between differing herbivore guilds.  相似文献   

14.
Plant invasions have tremendous potential to alter food webs by changing basal resources. Recent studies document how plant invasions may contribute to increased arthropod abundances in detritus-based food webs. An obvious mechanism for this phenomenon—a bottom-up effect resulting from elevated levels of detritus from the invasive plant litter—has not been explicitly studied. We examined the effects of an annual grass invasion on ground arthropod assemblages in the coastal sage scrub (CSS) of southern California. Bottom-up food web theory predicts that the addition of detritus would increase generalist-feeding arthropods at all trophic levels; accordingly, we expected increases in fungi, Collembola, and common predators such as mites and spiders. For the common ant taxa, habitat alteration may also be important for predicting responses. Thus we expected that Forelius mccooki and Pheidole vistana, the most common ant species, would decline because of changes in soil temperature (F. mccooki) and habitat structure (P. vistana) associated with litter. We studied trends observationally and conducted a 3-year experiment in which we manipulated litter quantity. In contrast to other published studies, most detritus-based arthropod taxa declined in areas of high grass invasion, and, within trophic levels, responses often varied idiosyncratically. For the two most common taxa, a native ant (F. mccooki), and predatory mites in the Anystidae, we experimentally linked declines in abundance to increased levels of invasive grass litter. Such declines, especially those exhibited by the most common ant taxa, could have cascading effects on the CSS ecosystem, where ants are numerically dominant and thus may have broad influences on food web and ecosystem properties. Our results highlight that accurately predicting arthropod responses to invasive plant litter requires careful consideration of the structural and food resources provided by detritus to each particular food web.  相似文献   

15.
While plant diversity is well known to increase primary productivity, whether these bottom-up effects are enhanced by reciprocal top-down effects from the third trophic level is unknown. We studied whether pine tree species diversity, aphid-tending ants and their interaction determined plant performance and arthropod community structure. Plant diversity had a positive effect on aphids, but only in the presence of mutualistic ants, leading to a threefold greater number of both groups in the tri-specific cultures than in monocultures. Plant diversity increased ant abundance not only by increasing aphid number, but also by increasing ant recruitment per aphid. The positive effect of diversity on ants in turn cascaded down to increase plant performance; diversity increased plant growth (but not biomass), and this effect was stronger in the presence of ants. Consequently, bottom-up effects of diversity within the same genus and guild of plants, and top-down effects from the third trophic level (predatory ants), interactively increased plant performance.  相似文献   

16.
1. Ants are important predators in agricultural systems, and have complex and often strong effects on lower trophic levels. Agricultural intensification reduces habitat complexity, food web diversity and structure, and affects predator communities. Theory predicts that strong top-down cascades are less likely to occur as habitat and food web complexity decrease. 2. To examine relationships between habitat complexity and predator effects, we excluded ants from coffee plants in coffee agroecosystems varying in vegetation complexity. Specifically, we studied the effects of eliminating ants on arthropod assemblages, herbivory, damage by the coffee berry borer and coffee yields in four sites differing in management intensification. We also sampled ant assemblages in each management type to see whether changes in ant assemblages relate to any observed changes in top-down effects. 3. Removing ants did not change total arthropod densities, herbivory, coffee berry borer damage or coffee yields. Ants did affect densities of some arthropod orders, but did not affect densities of different feeding groups. The effects of ants on lower trophic levels did not change with coffee management intensity. 4. Diversity and activity of ants on experimental plants did not change with coffee intensification, but the ant species composition differed. 5. Although variation in habitat complexity may affect trophic cascades, manipulating predatory ants across a range of coffee agroecosystems varying in management intensity did not result in differing effects on arthropod assemblages, herbivory, coffee berry borer attack or coffee yields. Thus, there is no clear pattern that top-down effects of ants in coffee agroecosystems intensify or dampen with decreased habitat complexity.  相似文献   

17.
Zhang S  Zhang Y  Ma K 《PloS one》2012,7(4):e35468
Ant-aphid mutualism is known to play a key role in the structure of the arthropod community in the tree canopy, but its possible ecological effects for the forest floor are unknown. We hypothesized that aphids in the canopy can increase the abundance of ants on the forest floor, thus intensifying the impacts of ants on other arthropods on the forest floor. We tested this hypothesis in a deciduous temperate forest in Beijing, China. We excluded the aphid-tending ants Lasius fuliginosus from the canopy using plots of varying sizes, and monitored the change in the abundance of ants and other arthropods on the forest floor in the treated and control plots. We also surveyed the abundance of ants and other arthropods on the forest floor to explore the relationships between ants and other arthropods in the field. Through a three-year experimental study, we found that the exclusion of ants from the canopy significantly decreased the abundance of ants on the forest floor, but increased the abundance of beetles, although the effect was only significant in the large ant-exclusion plot (80*60 m). The field survey showed that the abundance of both beetles and spiders was negatively related to the abundance of ants. These results suggest that aphids located in the tree canopy have indirect negative effects on beetles by enhancing the ant abundance on the forest floor. Considering that most of the beetles in our study are important predators, the ant-aphid mutualism can have further trophic cascading effects on the forest floor food web.  相似文献   

18.
Top-predator (fourth-trophic-level) controlled trophic cascades are thought to be uncommon in terrestrial systems, but actual quantitative tests and comparisons of bottom-up and top-down forces in systems with more than three linear trophic levels are rare. Here, we describe the density patterns of the arthropod community associated with Piper ant-plants in Costa Rican wet forests. Consumers in this community comprise a complex, interacting web of herbivores, predaceous ants, and predators of ants. Although the hollow stems and petioles of the Piper plants provide some protection to resident ants from predation, specialized Dipoena spiders and Phyllobaenus beetles exploit Pheidole ants inhabiting Piper plants. We report abundance patterns of plants, ants and predators in four forests. These patterns of abundance are consistent with predictions of top-down cascades across four trophic levels when the top predators are effective (beetles). We discuss how top-down and bottom-up forces may interact in systems with less effective top predators (spiders).  相似文献   

19.
Gruner DS  Taylor AD 《Oecologia》2006,147(4):714-724
A longstanding goal for ecologists is to understand the processes that maintain biological diversity in communities, yet few studies have investigated the combined effects of predators and resources on biodiversity in natural ecosystems. We fertilized nutrient limited plots and excluded insectivorous birds in a randomized block design, and examined the impacts on arthropods associated with the dominant tree in the Hawaiian Islands, Metrosideros polymorpha (Myrtaceae). After 33 months, the species load (per foliage mass) of herbivores and carnivores increased with fertilization, but rarified richness (standardized to abundance) did not change. Fertilization depressed species richness of arboreal detritivores, and carnivore richness dropped in caged, unfertilized plots, both because of the increased dominance of common, introduced species with treatments. Herbivore species abundance distributions were more equitable than other trophic levels following treatments, and fertilization added specialized native species without changing relativized species richness. Overall, bird removal and nutrient addition treatments on arthropod richness acted largely independently, but with countervailing influences that obscured distinct top-down and bottom-up effects on different trophic levels. This study demonstrates that species composition, biological invasions, and the individuality of species traits may complicate efforts to predict the interactive effects of resources and predation on species diversity in food webs.  相似文献   

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