The experimental manipulation of insect herbivore load by the use of an insecticide (malathion): The effect of application on plant growth

Summary The effects of insect herbivores on natural communities of plants may be demonstrated by manipulative experimetns. Such experiments, which reduce the natural levels of herbivory by application of insecticide, incorporate the assumption that the insecticide has no direct effect on the vegetation. A test of this assumption should therefore be an integral part of any study of herbivory employing chemical exclusion. Here a single compound (Malathion-60), which is commonly used in such studies, is tested both in the field and on selected plant species under controlled conditions. It was found to have no effect on a range of early successional plant species. The limitations of the tests are discussed.     

Predator diversity and density affect levels of predation upon strongly interactive species in temperate rocky reefs

Indirect effects of predators in the classic trophic cascade theory involve the effects of basal species (e.g. primary producers) mediated by predation upon strongly interactive consumers (e.g. grazers). The diversity and density of predators, and the way in which they interact, determine whether and how the effects of different predators on prey combine. Intraguild predation, for instance, was observed to dampen the effects of predators on prey in many ecosystems. In marine systems, species at high trophic levels are particularly susceptible to extinction (at least functionally). The loss of such species, which is mainly attributed to human activities (mostly fishing), is presently decreasing the diversity of marine predators in many areas of the world. Experimental studies that manipulate predator diversity and investigate the effects of this on strongly interactive consumers (i.e. those potentially capable of causing community-wide effects) in marine systems are scant, especially in the rocky sublittoral. I established an experiment that utilised cage enclosures to test whether the diversity and density of fish predators (two sea breams and two wrasses) would affect predation upon juvenile and adult sea urchins, the most important grazers in Mediterranean sublittoral rocky reefs. Changes in species identity (with sea breams producing major effects) and density of predators affected predation upon sea urchins more than changes in species richness per se. Predation upon adult sea urchins decreased in the presence of multiple predators, probably due to interference competition between sea breams and wrasses. This study suggests that factors that influence both fish predator diversity and density in Mediterranean rocky reefs (e.g. fishing and climate change) may have the potential to affect the predators' ability to control sea urchin population density, with possible repercussions for the whole benthic community structure.     

The macroecology of marine cleaning mutualisms

1. Marine cleaning mutualisms generally involve small fish or shrimps removing ectoparasites and other material from cooperating 'client' fish. We evaluate the role of fish abundance, body size and behaviour as determinants of interactions with cleaning mutualists. 2. Data come from eight reef locations in Brazil, the Caribbean, the Mediterranean and Australia. 3. We conducted a meta-analysis of client-cleaner interactions involving 11 cleaner and 221 client species. 4. There was a strong, positive effect of client abundance on cleaning frequency, but only a weak, negative effect of client body size. These effects were modulated by client trophic group and social behaviour. 5. This study adds to a growing body of evidence suggesting a central role of species abundance in structuring species interactions.     

基于自相关模式的动态心电图RR间期数据处理方法的研究

目的：在动态心电图分析过程中,确定RR间期,对于分析心电信息起着非常重要的作用。但是,临床上,实际检测的记录中,不可避免地受到外界很多的干扰,由于这些干扰信息的存在,使得准确定位RR间期变得非常困难。本课题拟在干扰情况下,提取心电表达的最大信息,达到准确定位RR间期的目的。方法：本研究运用自相关模式数据处理方法有效地提升了主峰、次峰强度间的差别,从而为更好地判断RR间期以及埋藏在噪音之中的QRS波信息提供了可能的方法。结果：我们用了自相关模式数据处理的方法获得了以下信息：（1）对于干扰小的心电信息,主峰与次峰间的强度比值由2.7倍提升到7.7倍。（2）对于干扰大的心电信息,即那些主峰已经被现有Holter处理软件及医生人工判断都认为不可以使用的数据,因为这些数据主峰强度明显小于次峰强度（主峰/次峰〈1）,经过我们的方法处理后,可以使主峰强度与次峰强度之比提升到1.5（主峰/次峰〉1.5）,从而使得RR间期可以进行清晰分辨。结论：在心电信息受到干扰的情况下,它的RR间期很难判断,运用本研究使用的自相关模式数据处理方法,能够提升动态心电图中主峰与次峰的强度比值,提高人工判断RR间期的准确性。所以,基于自相关模式的动态心电图RR间期数据处理方法是行之有效的。     

Scaling up: examining the macroecology of ectomycorrhizal fungi

Ectomycorrhizal (ECM) fungi play major ecological roles in temperate and tropical ecosystems. Although the richness of ECM fungal communities and the factors controlling their structure have been documented at local spatial scales, how they vary at larger spatial scales remains unclear. In this issue of Molecular Ecology, Tedersoo et al. (2012) present the results of a meta‐analysis of ECM fungal community structure that sheds important new light on global‐scale patterns. Using data from 69 study systems and 6021 fungal species, the researchers found that ECM fungal richness does not fit the classic latitudinal diversity gradient in which species richness peaks at lower latitudes. Instead, richness of ECM fungal communities has a unimodal relationship with latitude that peaks in temperate zones. Intriguingly, this conclusion suggests the mechanisms driving ECM fungal community richness may differ from those of many other organisms, including their plant hosts. Future research will be key to determine the robustness of this pattern and to examine the processes that generate and maintain global‐scale gradients of ECM fungal richness.     

Optimal behaviour sampling and autocorrelation curve: modelling data of farmed foxes

Behavioural investigations frequently make use of video recordings. In a typical study, behaviour is recorded during a 24-h period using instantaneous sampling, a method whereby consecutive samples taken from the same animal are autocorrelated. This study sought to model the autocorrelation function and to evaluate the optimal sampling interval for recording periods of different length in farmed blue foxes. The data were based on video recordings. The autocorrelation was found to have two components: short-range and long-range. The range of the short-range component was from 2 to 4 min, implying that an animal continues the same operation without interruption for several minutes. The duration of the long-range component was from 20 to 75 min and was affected by the animals mental state. The optimal sampling interval was not the same for all the behaviours studied and, moreover, depended on the length of the recording period. If the recording period lasted for 3 to 5 days, the optimal sampling interval was from 10 to 15 min; if, however, there was only one recording day, the optimal sampling interval was from 4 to 6 min.     

Rarity in the tropics: biogeography and macroecology of the primates

Aim To describe rarity and elucidate its biology in a tropical mammalian order, the Primates. Location Africa, Central and South America, Asia, Madagascar. Methods A review of the literature, with some additional analyses using data from the literature. A variety of definitions of rarity are used in order to describe it and to investigate its biology by correlating the degree of rarity with a variety of biological traits indicative of resource use (e.g. size of annual home range), reproductive rate (e.g. birth interval)and specialization (e.g. number of habitat types used). Results Few primate taxa occur outside the tropics, and most taxa are rare (small geographical range size or latitudinal extent, low density or both). Latitudinal extent is narrower at lower latitudes in Africa and Asia, but the potential resultant packing of taxa appears not to explain the taxonomic diversity gradient. Whilst primate species do not show the common, positive density by range size relationship, primate genera show a significant shallow slope, and primate families/subfamilies a strongly positive slope. Rare taxa are specialized, but neither use more resources nor breed more slowly than common taxa. The correlation of rarity and specialization is via geographical range: taxa with small ranges, or small ranges for their density, are specialized, but not taxa at low density. Common taxa are generalized because they consist of more differently specialized subtaxa, not because each subtaxon is generalized. Main conclusions Most primate taxa are rare, in which case most are presumably likely to go extinct. Rare primates are specialized, but do not necessarily use more resources, nor breed more slowly. Specialization as an explanation for rarity appears to work via constriction of range size, not of density. Common primates might be common (large range size) not because subtaxa or individuals are generalized, but because they are composed of more subtaxa. A consequence could be that persistence of even common taxa will depend on conservation of several populations scattered across the taxon's geographical range.     

Multimodal Observation Method of Digital Accessibility for Elderly People

This article presents a new methodological framework for multimodal observation of digital technologies. It is based on the use of mixed methods developed in the interdisciplinary MAN project founded by CNRS. It focuses on the digital accessibility of older people. The originality of the method lies in the implementation of a method combining qualitative and quantitative measurement to determine relevant indicators. These indicators characterize the person's behavior when using a technology and its usability. We show how these indicators are built, based on the cross-referencing of data. We present the different tools (questionnaire, interviews and technological data recording tools) used in the MAN method in a living laboratory environment controlled with four volunteers. Two use scenarios are proposed to illustrate the method in assessing the accessibility of a tactile application for older people without a digital divide and without disabilities. We present the recorded qualitative and quantitative data and illustrate by an example the unrelatedness of these data through a specific annotation tool.     

The macroecology of population dynamics: taxonomic and biogeographic patterns in population cycles

Regular cycles in population abundance are fascinating phenomena, but are they common in natural populations? How are they distributed among taxa? Are there differences between different regions of the world, or along latitudinal gradients? Using the new Global Population Dynamics Database we analysed nearly 700 long (25 + years) time series of animal field populations, looking for large-scale patterns in cycles. Nearly 30% of the time series were cyclic. Cycle incidence varied among taxonomic classes, being most common in mammal and fish populations, but only in fish did cycle incidence vary among orders. Cycles were equally common in European and North American populations, but were more common in Atlantic fish than Pacific fish. The incidence of cycles increased with latitude in mammals only. There was no latitudinal gradient in cycle period, but cycle amplitude declined with latitude in some groups of fish. Even after considering the biases in the data source and expected type I error, population cycles seem common enough to warrant ecological attention.     

Year-to-year Oscillations in Demography of the Strictly Biennial <Emphasis Type="Italic">Pedicularis sylvatica</Emphasis> and Effects of Experimental Disturbances

In 1998–2001, I studied disturbance effects on the population structure and dynamics of a grassland strict biennial Pedicularis sylvatica, and on the species demography (monthly dynamics of seedling recruitment in 1998 and within- and between-year survival in 1998–2000). In two Czech populations, I established three experimental disturbance regimes: (1) a gap treatment, that simulated grazing by clipping vegetation and creating small gaps, (2) a mowing treatment, where I clipped the vegetation, and (3) a no management treatment, where I left the vegetation untreated. The number of recruiting seedlings varied greatly by year, and demographic structure of populations showed significant year-to-year oscillations in mean seedling numbers, from low (3 ± 0.7 s.e. per 0.25 m² plot) to high (103 ± 20). Inversely in the same years and plots, mean adult numbers in populations oscillated from high (12 ± 2) to low (0.7 ± 0.3). Disturbance effects were only important for seedling recruitment in early census dates in all years. In 1998, most seedlings recruited in April–May in gaps in both sites, but most died before winter. Within- and between-year survival was not affected by disturbance regimes but fluctuated significantly among years. Between-year survival increased with increasing size of the overwintering bud and was higher in disturbance treatments. Since the oscillations in population structure did not significantly vary in response to experimental disturbances, population dynamics may be driven endogenously rather than by disturbance events. The weak disturbance effects on species demography may also indicate population resilience to changes in habitat quality. However, since disturbances promoted seedling recruitment, grazing or mowing regimes are strongly recommended, as they create regeneration opportunities and maintain habitat quality, meeting the species long-term conservation goals.     

锁定钢板与保守治疗老年肱骨外科颈骨折的临床疗效比较

目的:探讨锁定钢板与保守治疗在老年肱骨外科颈骨折患者中的临床疗效及安全性。方法:收集我院就诊的124例肱骨外科颈骨折患者,随机分为实验组和对照组,每组各62例。实验组患者给予肱骨近端的锁定加压钢板术,对照组患者给予保守治疗。观察并比较两组患者治疗前后肩关节Constant评分、疼痛视觉模拟评分(VAS)水平、临床治疗有效率以及并发症发生情况。结果:与治疗前相比,两组患者治疗后的肩关节Constant评分水平均升高,VAS评分水平均下降,差异具有统计学意义(P0.05);与对照组相比,实验组患者的肩关节Constant评分水平均较高,VAS评分水平较低,差异具有统计学意义(P0.05);与对照组相比,实验组患者临床治疗有效率较高,并发症发生率较低,差异具有统计学意义(P0.05)。结论:相比于保守治疗,锁定钢板对于老年的肱骨外科颈骨折的疗效和安全性均较高。     

一种天敌控制多种害虫作用的模糊数学评价方法

从生物防治的基本思想出发,利用模糊数学和生态经济的原理,探讨天敌的作用,建立了一种天敌控制多种害虫的模糊数学评判方法,文中给出了一种天敌对害虫的影响率和影响强度、一种天敌对害虫影响的大小以及天敌对害虫的控制能力,并进行了控制分析。     

Temporal and spatial variation in an index of biological integrity for the middle Wabash River, Indiana

Few studies have addressed within-year temporal variation of IBI scores. We compared index of biotic integrity (IBI) scores for two summer sampling events from a large river during 25 annual periods. The results indicated that IBI scores calculated from June samples were not significantly different from July samples. Spatial autocorrelation was present, such that sites that were closer together produced similar IBI scores and could not be considered independent. Temporal autocorrelation was present, but was not strong. Lower quality sites (low IBI score) did not have higher variation than higher quality sites. Our results show that a single sample of fishes by boat electrofisher during the summer in a large river such as the Wabash River can produce a repeatable estimate of IBI score. Thus, repeated or additional sampling within the summer season to improve the quality of the evaluation is not warranted. Handling editor: J. Trexler