温度对两种蓝藻种间竞争的影响

通过室内实验研究了不同温度条件下主要水华藻类——铜绿微囊藻(Microcystis aeruginisa)和巨颤藻(Oscillatoria princeps)的生长和种间竞争。结果表明:无论在纯培养体系还是混合培养体系中,微囊藻在25℃下生长最好,颤藻在30℃下生长最好;温度对藻类的种间竞争抑制参数能够产生明显影响,在20℃、25℃、30℃3个温度下,颤藻对微囊藻的竞争抑制参数随温度的升高而升高,30℃时颤藻对微囊藻的竞争抑制参数分别是20℃和25℃时的1.42倍和1.13倍,微囊藻对颤藻的竞争抑制参数则表现为25℃>30℃>20℃,25℃时微囊藻对颤藻的竞争抑制参数分别是20℃和30℃时的1.54倍和1.21倍,在20℃、25℃、30℃3个温度下,微囊藻对颤藻的竞争抑制参数均大于颤藻对微囊藻的竞争抑制参数,说明在各试验温度下,微囊藻对颤藻的抑制能力均大于颤藻对微囊藻的抑制能力;根据Lotka-Volterra竞争模型中的两物种竞争结果可初步判断,20℃和25℃温度下,微囊藻在竞争中取胜,30℃下,微囊藻和颤藻可以实现不稳定共存。     

The interspecific competition between Humulus scandens and Alternanthera philoxeroides

Bioinvasion has become a serious environmental problem in the world in general and is considered the second biggest threat to biodiversity. Alternanthera philoxeroides is widely distributed and causes the most serious threat to biodiversity in China. The traditional physical or biological control methods are not effective in controlling the invasion and extension of A. philoxeroides. In the present paper, some physiological characteristics of Humulus scandens and A. philoxeroides were investigated in the field and laboratory. The results showed that H. scandens is more competitive than A. philoxeroides, the competitive rate (CR) of H. scandens against A. philoxeroides was 9.834. Additionally, the leaf, stem, and root biomass of A. philoxeroides decreased significantly when the two species co-occurred. Thus, the invasive abilities of these two invasive plants are different and H. scandens strongly inhibited the growth of A. philoxeroides. Moreover, as an annual herb, H. scandens can be easily eliminated by harvesting before its seeds mature. The result suggests that sowing seeds of H. scandens in the habitats invaded by A. philoxeroides could be an ideal biological control method.     

Effects of glyphosate on interspecific competition between Solidago canadensis and Imperata cylindrica

Aims The extensive use of herbicide to control invasive plants would change the relationship between alien and neighboring plants. In order to provide data for rational use of herbicide and a theoretical reference for further studies on the ecological effects of glyphosate, we explored the variation of the relationship between an invasive plant Solidago canadensis and a native plant Imperata cylindrica when they were sprayed glyphosate.
Methods A replacement series experiment was conducted from June to August 2016 in Wetland Ecosystem Research Station of Hangzhou Bay, State Forestry Administration, to examine the effects of glyphosate at seven concentration levels (0, 0.3, 0.6, 0.9, 1.2, 1.5, 1.8 mL·L^-1) on the growth and interspecific competition of S. canadensis and I. cylindrica.
Important findings (1) Glyphosate treatment significantly inhibited the growth of S. canadensis and I. cylindrica (p < 0.05). During the test, cumulative growth of height and leaf number of S. canadensis were apparently reduced with the increase of glyphosate concentration, but the leaf number of S. canadensis treated with 0.3- 1.5 mL·L^-1 glyphosate was re-growing with time, while the one treated with 1.8 mL·L^-1 was mostly dead. The withering rate of tiller and green leaf of I. cylindrica also significantly increased with the increase of glyphosate concentration, and the growth indices of this plant treated with 0.3-0.6 mL·L^-1 were also re-growing with time. (2) Glyphosate treatment significantly affected interspecific competition (p < 0.05), which diminished as the glyphosate concentration increased. (3) Interspecific competition has significant influence on the biomass allocation of S. canadensis (p < 0.05). When facing competition, S. canadensis would allocate more organic matter to root and thus increase the ratio of root to shoot. Competition only inhibited the tiller number and total biomass of I. cylindrica, but insignificantly affected its ratio of root to shoot. (4) The interaction between glyphosate treatment and S. canadensis-I. cylindrica interspecific relationship also significantly influenced the biomass of S. canadensis and I. cylindrica (p < 0.05), but insignificantly affected the root/shoot ratio of two plants. Different plants have different tolerance to glyphosate stress. Compared with native plant I. cylindrica, S. canadensis has stronger tolerance to glyphosate. Low-concentration glyphosate could decrease the competitive intensity between S. canadensis and I. cylindrica, which may disturb the structure and dynamics of plant communities.     

光肩星天牛与星天牛种间竞争行为研究

光肩星天牛Anoplophora glabripennis和星天牛Anoplophora chinensis是我国两种重要的林业蛀干害虫,存在很多共同的寄主植物。为了阐明两种星天牛之间的物种竞争关系,本文采用行为观察试验,研究两种星天牛寄主危害部位、异种危害寄主识别和种间争斗行为等试验。结果显示,光肩星天牛和星天牛在寄主植物上的取食危害部位有很大差异,光肩星天牛主要取食寄主植物的枝条上部,取食面积为2 390.0 mm²,占整个寄主植物取食面积的69.3%,星天牛主要取食寄主植物的树干上部,取食面积为3 140.0 mm²,占整个寄主植物的96.6%;两种星天牛都能识别异种天牛危害过的寄主,对其具有显著的回避性,其中光肩星天牛对星天牛危害过的寄主取食量平均值为420.8 mm²,显著低于健康寄主取食量平均值2 518.8 mm²,同样,星天牛对光肩星天牛危害过的寄主取食量平均值为436.8 mm²,显著低于健康寄主取食量平均值1 803.5 mm²,而对同...     

Foraging site use and interspecific competition between bluegills and golden shiners

Synopsis Laboratory experiments examined the foraging performances of a dietary generalist, bluegill,Lepomis macrochirus, and a dietary specialist, golden shiner,Notemigonus crysoleucas, as they fed from devices simulating four foraging sites (bottom substrate, water column, submerged macrophytes, and water surface). Fishes foraged in monospecific and mixed-species groups of two and four individuals. For monospecific groups, foraging rates of bluegills did not differ among the four sites, but golden shiners had significantly higher rates on bottom and midwater sites than on plant and surface sites. The size of monospecific groups did not affect foraging rates of either species. In mixed-species trials, bluegills removed more food items than golden shiners from plant and surface sites in two- and four-fish groups and from bottom sites in two-fish groups. Bluegills' foraging performances improved with experience, golden shiners' performances did not. Experimental results are discussed with respect to interactions between bluegills and golden shiners in natural assemblages.     

接种AMF对菌根植物和非菌根植物竞争的影响

为了研究丛枝菌根真菌(arbuscular mycorrhizal fungus, AMF)对菌根植物与非菌根植物种间竞争的影响,以玉米(菌根植物)和油菜(非菌根植物)作为供试植物,分别进行间作、尼龙网分隔和单作,模拟这两种植物之间不同的竞争状态,接种丛枝菌根真菌Glomus intraradices和Glomus mosseae,比较菌根植物和非菌根植物的生长和磷营养状况,分析AMF侵染对植物种间竞争作用的影响。结果显示,与单作相比,间作模式下玉米的生物量及磷营养状况有所降低,但其菌根依赖性却有所提高。与不接种相比,接种处理显著降低了间作体系油菜根系的磷含量和磷吸收量,但趋于改善菌根植物玉米的磷营养状况。因此,接种AMF可以降低非菌根植物的磷营养状况及生物量,使得菌根植物的相对竞争能力明显提高,说明AMF在维持物种多样性方面有着重要的作用。     

轮虫和枝角类的种间竞争及其影响因子研究进展

轮虫和枝角类是浮游动物群落的重要组成部分和优势类群,它们之间的竞争互作是调节水生态系统结构和功能的主要动力之一。普遍的观点认为,轮虫和大型枝角类难以共存,往往被竞争排斥,而和小型枝角类可以共存;实际上,轮虫和枝角类的种间竞争结局存在一定的不确定性。介绍了轮虫和枝角类的种间竞争方式及其相对重要性,对影响轮虫和枝角类种间竞争结局的因素,包括温度、食物、相对起始密度、个体大小、食物临点、耐饥饿能力、捕食及竞争者和捕食者释放的化感物质等,进行了系统的梳理和分析,并提出了今后亟待解决的科学问题和研究切入点。     

氮和磷浓度对中肋骨条藻和锥状斯氏藻种间竞争的影响

采用室内单养和混养方法, 设置不同的氮、磷营养条件, 研究了氮、磷对中肋骨条藻(Skeletonema costatum)和锥状斯氏藻(Scrippsiella trochoidea)种间竞争的影响。结果表明: 混养时各氮和磷浓度下均呈现培养初期中肋骨条藻为优势种、培养后期锥状斯氏藻为优势种的变化趋势, 但随着氮、磷浓度的升高, 中肋骨条藻作为优势种的时间延长; 与单养时相比, 混养中两种微藻的最大密度受到不同程度的抑制, 表现出氮、磷浓度越高, 受抑制的程度越大的特征, 且与锥状斯氏藻相比, 中肋骨条藻的最大密度受到抑制的程度更大。混养时两种微藻均是在氮、磷浓度最高时, 抑制起始点出现时间最长, 随着氮、磷浓度的降低, 抑制起始点出现时间缩短; 各氮、磷浓度条件下, 锥状斯氏藻对中肋骨条藻的竞争抑制参数明显高于中肋骨条藻对锥状斯氏藻的竞争抑制参数, 当氮浓度为512 μmol·L^-1、磷浓度为2 μmol·L ^-1时, 竞争结果是锥状斯氏藻获胜; 其余氮、磷浓度条件下为两种微藻不稳定共存。     

米氏凯伦藻与东海原甲藻共培养条件下的种群竞争

米氏凯伦藻(Karenia mikimotoi)与东海原甲藻(Prorocentrum donghaiense)为有害赤潮生物,两者经常形成复合型赤潮.该文设置东海原甲藻的起始密度为400 cells·mL-1,米氏凯伦藻分别为200 cells·mL-1、400 cells·mL-1和800 cells·mL-1,通过共培养实验,初步研究米氏凯伦藻和东海原甲藻的种间关系.结果表明:共培养条件下,受到东海原甲藻的影响,米氏凯伦藻的生长受到抑制.米氏凯伦藻不同的起始密度对东海原甲藻的生长有不同的影响,较低的起始密度(200 cells·mL-1、400cells·mL-1)促进东海原甲藻的生长,使其增长率提高,生长曲线达到拐点的时间提前;高的起始密度(800 cells·mL-1)对东海原甲藻的生长有一定的抑制作用,使其增长率降低,生长曲线达到拐点的时间推迟.     

Transgenerational effect alters the interspecific competition between two dominant species in a temperate steppe

One of the key aims of global change studies is to predict more accurately how plant community composition responds to future environmental changes. Although interspecific relationship is one of the most important forces structuring plant communities, it remains a challenge to integrate long‐term consequences at the plant community level. As an increasing number of studies have shown that maternal environment affects offspring phenotypic plasticity as a response to global environment change through transgenerational effects, we speculated that the transgenerational effect would influence offspring competitive relationships. We conducted a 10‐year field experiment and a greenhouse experiment in a temperate grassland in an Inner Mongolian grassland to examine the effects of maternal and immediate nitrogen addition (N) and increased precipitation (Pr) on offspring growth and the interspecific relationship between the two dominant species, Stipa krylovii and Artemisia frigida. According to our results, Stipa kryloii suppressed A. frigida growth and population development when they grew in mixture, although immediate N and Pr stimulated S. kryloii and A. frigida growth simultaneously. Maternal N and Pr declined S. krylovii dominance and decreased A. frigida competitive suppression to some extent. The transgenerational effect should further facilitate the coexistence of the two species under scenarios of increased nitrogen input and precipitation. If we predicted these species'' interspecific relationships based only on immediate environmental effects, we would overestimate S. krylovii''s competitive advantage and population development, and underestimate competitive outcome and population development of A. frigida. In conclusion, our results demonstrated that the transgenerational effect of maternal environment on offspring interspecific competition must be considered when evaluating population dynamics and community composition under the global change scenario.     

Species coexistence under resource competition with intraspecific and interspecific direct competition in a chemostat

Competition theory has developed separately for direct competition and for exploitative competition. However, the combined effects of the two types of competition on species coexistence remain unclear. To examine how intraspecific and interspecific direct competition contributes to the coexistence of species competing for a single resource, we constructed a chemostat-type resource competition model. With general functions for intraspecific and interspecific direct competition, we derived necessary and sufficient conditions (except for a critical case that rarely occurs in a biological sense) that determine the number of stably coexisting species. From these conditions, we found that the number of coexisting species is determined just by the invasibility of each species into subcommunities with a smaller number of species. In addition, using a combination of rigorous mathematical theory and a simple graphical method, we can demonstrate how the stronger intraspecific direct competition facilitates species invasion, leading to a larger number of coexisting species.     

Cooperative colony founding alters the outcome of interspecific competition between Amazonian plant-ants

In myrmecophytes, plants with structures in which ants establish colonies, there is strong competition among ant queens for access to host plants. However, our knowledge of how queens of different partner species interact when attempting to colonize plants remains limited. The Amazonian myrmecophyte Maieta guianensis is colonized by queens of two ant species: Crematogaster laevis and Pheidole minutula. We elucidated the competitive ranking of queens of these species and tested the hypothesis that cooperative colony founding (pleometrosis) by P. minutula queens could alter this ranking. We found that C. laevis queens are behaviorally dominant to P. minutula when individual queens encounter each other. Despite being inferior in combat, however, P. minutula queens successfully colonized seedlings at similar rates whether they were placed alone or in concert with a C. laevis queen. This may have occurred because the smaller P. minutula queens frequently entered domatia before the more robust C. laevis queens. Although C. laevis queens can evict P. minutula queens that had previously colonized domatia, this was an infrequent phenomenon—perhaps because while not fatal, conflicts often resulted in serious injury. Furthermore, by colonizing the same plant cooperative P. minutula queens dramatically reduce the probability that C. laevis colonizes host-plants without reducing their own per capita rates of colonization success. To our knowledge, this is a novel benefit of pleometrosis, whose primary advantages have primarily been thought to occur after the critical stage of colony establishment. Given the decreased likelihood of colonization when faced with multiple P. minutula, it may be that C. laevis’ persistence at the landscape level is enhanced by such factors as priority effects, superior dispersal ability, or niche partitioning.     

The influence of sediment mobility and channel geomorphology on periphyton abundance

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不同混种密度下杀真菌剂对黄顶菊与反枝苋种间竞争的影响

为探究AM真菌共生对黄顶菊(Flaveria bidentis)与本地物种间竞争关系的影响,开展了不同种植比例条件下杀真菌剂对黄顶菊与反枝苋(Amaranthus retroflexus)的种间竞争试验。结果表明:黄顶菊是一种菌根真菌(AM)高度依赖性植物,杀真菌剂处理对其竞争效应产生了显著影响;在添加杀真菌剂条件下黄顶菊的相对产量在黄顶菊与反枝苋种植比例为1∶2、1∶1、2∶1条件下均1.0,而反枝苋的相对产量均1.0,且两者混种时的相对产量总和在黄顶菊与反枝苋种植比例为1∶2、1∶1、2∶1条件下均1.0,这说明反枝苋相对于黄顶菊而言是一种较强的竞争者,两者需要相同的资源;不添加杀真菌剂条件下,黄顶菊植株全氮、全磷含量分别增加1.1~1.6倍和1.1~1.2倍,而反枝苋的全氮、全磷含量无明显变化;AM真菌共生可能通过菌根介导的化感互作影响外来入侵植物与土著植物竞争格局,且受外界环境条件影响,这种共生关系可以减缓外界胁迫对共生植物不利的影响。     

Maternal effects and the outcome of interspecific competition

1. Maternal environmental effects create lagged population responses to past environments. Although they are ubiquitous and vary in expression across taxa, it remains unclear if and how their presence alters competitive interactions in ecological communities.
2. Here, we use a discrete‐time competition model to simulate how maternal effects alter competitive dynamics in fluctuating and constant environments. Further, we explore how omitting maternal effects alter estimates of known model parameters from observational time series data.
3. Our simulations demonstrate that (i) maternal effects change competitive outcomes, regardless of whether competitors otherwise interact neutrally or exhibit non‐neutral competitive differences, (ii) the consequences of maternal effects for competitive outcomes are mediated by the temporal structure of environmental variation, (iii) even in constant conditions, competitive outcomes are influenced by species'' maternal effects strategies, and (iv) in observational time series data, omitting maternal effects reduces variation explained by models and biases parameter estimates, including competition coefficients.
4. Our findings demonstrate that the ecological consequences of maternal effects hinge on the competitive environment. Evolutionary biologists have long recognized that maternal effects can be an important but often overlooked strategy buffering populations from environmental change. We suggest that maternal effects are similarly critical to ecology and call for research into maternal effects as drivers of dynamics in populations and communities.

     

起始生物量比对3种海洋微藻种间竞争的影响

为深入了解饵料微藻与赤潮微藻间的种间竞争关系,通过微藻共培养的方法,研究了起始生物量比(1:4、1:1和4:1)对3种海洋微藻(塔玛亚历山大藻、蛋白核小球藻和湛江等鞭金藻)两两之间种间竞争的影响,并对其作用机制进行了探讨。结果表明:①3种海洋微藻表现出种间竞争的相互抑制效应;②在与塔玛亚历山大藻(简称A)的种间竞争中,蛋白核小球藻(简称C)和湛江等鞭金藻(简称I)均在竞争中占优势,蛋白核小球藻随自身起始生物量比的提高,其竞争优势越加明显,湛江等鞭金藻在A:I=1:1时竞争优势最为明显;在蛋白核小球藻和湛江等鞭金藻的种间竞争中,当C:I=1:4时,湛江等鞭金藻在竞争中占优势,C:I=1:1时,初期湛江等鞭金藻占竞争优势,随蛋白核小球藻的迅速生长,后期蛋白核小球藻占竞争优势,C:I=4:1时,蛋白核小球藻占绝对竞争优势;③由种间竞争抑制参数比较得出:3种微藻的种间竞争强弱依次为蛋白核小球藻>湛江等鞭金藻>塔玛亚历山大藻。蛋白核小球藻和湛江等鞭金藻在起始比例C:I=1:1时,可共培养利用,在海产经济动物育苗中可对其进行适时采收投喂;两种饵料藻对塔玛亚历山大藻具有明显的抑制作用,可为开发利用饵料藻进行赤潮生物防控提供一定的科学依据。     

Bottleneck effect on intra- and interspecific competition in Drosophila malerkotliana

Intra and interspecific competition experiments involving control and bottleneck lines of monomorphic and polymorphic populations of D.malerkotliana with D.nasuta nasuta have been carried out. Productivity and population size were evaluated in these lines. The results show that control line had higher relative fitness and adaptedness (productivity and population size) under both intra and interspecific competition than their respective bottleneck lines and D.nasuta nasuta. This indicates that bottlenecks have an effect on competition in D.malerkotliana. The consequence of such competition studies using control and bottleneck lines of D.malerkotliana and D.nasuta nasuta is discussed.     

天柱山黄山松种内与种间竞争的研究

研究无菌条件下不同浓度砷对蜈蚣草的孢子萌发、假根和原叶体生长发育的影响。结果表明,培养基质中As浓度大于30mg/L时,孢子萌发速度、假根和原叶体的生长发育受到抑制,假根的着生点位置发生改变;而与高浓度As影响不同的是,低浓度As(30mg/L)可促进孢子变绿的速率和初期原叶体(播后8d内)的生长。因此,高浓度As能抑制配子体生长发育并改变假根着生点位置,而低浓度As则可促进配子体早期的生长。