Microbiota, fauna, and mesh size interactions in litter decomposition

Plant litter decomposition is a key process in carbon and nutrient cycling. The critical role of soil-faunal community composition in decomposition has been demonstrated using different mesh size litterbags to control exposure of litter to different faunal size classes. However, the faunal community surrounding the litterbags has not been manipulated despite potentially large indirect effects of their activity on biotic and abiotic processes that control litter decomposition at the habitat-scale.
We combined microcosm and litterbag techniques to facilitate a more comprehensive understanding of the role of direct and indirect effects of soil-faunal community composition on litter decomposition. We placed litterbags of three mesh sizes across model grassland miniecosystems manipulated to enable communities containing 1) microfauna; 2) micro- and meso-fauna; 3) micro-, meso- and macro-fauna. All communities contained bacteria and fungi. The approach permitted correction of mesh size artefacts inherent to field studies. Indirect effects have been divided into two separate terms, direct-indirect effects and indirect effects.
Decomposition in micromesh litterbags was significantly decreased by the indirect effects of meso- and macro-fauna. In macrofauna communities, increased mesh size significantly increased decomposition through mesh size per se and faunal effects. Relative effects of manipulated faunal community composition on litter mass loss and C:N ratio were equivalent for green and senesced litter. The presence of meso- and macro-fauna increased litter decomposition rate overall despite inhibiting decomposition by microfauna, bacteria and fungi through indirect effects.     

The structure and diurnal variations of the zooplankton of the Prince Edward Islands: Implications for the biomass build-up of higher trophic levels

Summary Short-term variations in the micro-, meso- and macrozooplankton communities at shelf and offshore stations in the vicinity of the Price Edward Islands were examined during April/May 1985 and 1986. Microzooplankton was dominated by copepod nauplii. Other holoplanktonic groups were represented in large numbers, while meroplanktonic larvae of benthic invertebrates were very scarce despite the large benthic population of the island shelf. Copepods dominated in terms of numerical abundance the meso- and macrozooplankton assemblage but cuphausiids were also very important in terms of biomass contribution. Dirunal vertical migrations were most pronounced for the euphausiids and the copepod Metridia gerlachei. The copepods Eucalanus longipes, Rhincalanus gigas and Microsetella sp. showed significant, but lesser, diurnal vertical migrations. A daylight decrease in zooplankton biomass was observed consistently on the island shelf, compared to the pattern found in deep-water. Data from daytime tows collected during April/May 1983 show that zooplankton biomass in the area increases with depth up to a stability level of about 50 mg/m³ (dry weight). It is suggested that an interaction between vertical migrations, surface Ekman drift and bottom topography results in zooplankton mass depletion by visual predators during daytime and replenishment during the night. The nocturnal advection of allochtonous zooplankton into the area may represent an input of food supply equivalent to as much as 2.2 times the local maximum phytoplankton production.     

豚草入侵对中小型土壤动物群落结构特征的影响

豚草(Ambrosia artemisiifolia)是菊科豚草属的恶性杂草,在我国华南地区已成功入侵并造成严重危害。为了解豚草入侵对中小型土壤动物群落的影响效应,采用野外样地试验法研究了豚草入侵地中小型土壤动物的群落特征。全年4次采样共获得中小型土壤动物4174头,隶属于4门11纲26类,其中线虫类为优势类群,蜱螨目和弹尾目是常见类群。结果显示,豚草入侵改变了中小型土壤动物群落的结构特征,入侵地中小型土壤动物的总个体数以及线虫类、弹尾目动物的个体数显著增加,但中小型土壤动物类群数的变化不明显;在群落的物种多样性方面,豚草入侵显著提高了群落的密度-类群指数,物种丰富度、优势度指数亦有所上升,但差异不明显,而均匀度、Shannon-Wiener指数则趋于下降;在群落相似性方面,入侵区与其它处理区的差异较小。豚草入侵所引起的局部气候环境、凋落物、根系分泌物与土壤理化性质的变化可能是造成中小型土壤动物群落结构特征改变的主要原因。     

Mercury intrusion porosimetry,nitrogen adsorption,and scanning electron microscopy analysis of pores in skin

Stability of collagenous matrixes such as skin and leather with respect to changes in their dimensions on heating has long been correlated with degree and type of cross links formed and short-range ordering in angstrom unit scales. Macroscopic dimensional changes may be expected to involve alterations in the long-range order as well as supramolecular assemblies in skin and leather. This study relates thermal shrinkage of skin matrixes with alterations observed in micro-, meso-, and macroporic structures. Changes in the pore structure of skin associated with thermal shrinkage have been studied using nitrogen adsorption and mercury intrusion porosimetry measurements. A comparison of results obtained using both techniques has been made. These results indicate that although the percentage porosity of the matrix decreases, the BET specific surface area increases on shrinkage. An insight into the changes in the pore systems of skin induced by thermal shrinkage has been gained.     

若尔盖高寒草甸退化对中小型土壤动物群落的影响

土壤动物是陆地生态系统物质循环和能量流动的中心环节,也是生态系统演化的重要驱动因子。为了查明青藏东缘若尔盖高寒草甸生态系统退化过程对中小型土壤动物群落的影响,2008年7、10两月分别对若尔盖高寒草甸沼泽草甸、草原草甸和沙化草甸三个不同退化阶段的中小型土壤动物群落进行了调查。共分离到中小型土壤动物9450个,隶属于4门5纲12目70科104类;优势类群为线虫（Nematode）,个体数占85.79%;蜱螨目（Arachnida）、弹尾目（Collembola）、寡毛纲（Oligochaeta）和昆虫纲（Insect）依次占8.73%、3.24%、1.32%和0.88%。群落密度、类群数、Margalef丰富度指数和密度-类群指数均在7、10两月份均随高寒草甸的退化而显著降低（p<0.01或p<0.05）,10月份的差异更明显。Shannon-wiener多样性指数、Pielou均匀性指数和Simpson优势度指数无显著变化（p>0.05）。各主要类群个体数在群落中所占的比例呈波动性变化,但沙化可使蜱螨目的数量相对提高,而弹尾目相对下降。随退化程度的加重,三个退化阶段的Sorenson群落相似性逐渐降低,而Morisita-Horn相似性的变化则不同,说明高寒草甸的退化对中小型土壤动物群落物种组成的影响较大,对群落优势类群数量的影响较小。10月份的群落密度、多样性和群落相似性均高于7月份,表明群落结构组成受季节的影响;但是各退化阶段的Sorenson和Morisita-Horn季节相似性比较说明,季节变化对沙化草甸种类组成的影响大于草原草甸,对草原草甸群落优势类群数量的影响大于沙化草甸。个体密度和类群数的表聚性程度也随退化加重而降低。以上研究结果表明,高寒草甸的退化能够降低土壤动物群落的组成种类和结构复杂性,将会影响其生态服务功能。     

川西亚高山森林凋落物分解初期土壤动物对红桦凋落叶质量损失的贡献

2010年10月26日-2011年4月18日在川西亚高山地区季节性冻融期间,选择典型的红桦-岷江冷杉林,采用凋落物分解袋法调查了不同网孔(0.02、0.125、1和3 mm)凋落物分解袋内的凋落物质量损失,分析微型、中型和大型土壤动物对红桦凋落叶分解的贡献.结果表明:在季节性冻融期间,0.02、0.125、1和3 mm分解袋内的红桦凋落叶质量损失率分别为11.8％、13.2％、15.4％和19.5％,不同体径土壤动物对红桦凋落叶质量损失的贡献率为39.5％;不同孔径凋落物袋内土壤动物的类群和个体相对密度与凋落叶的质量损失率的变化趋势相对一致.在季节性冻融的初期、深冻期和融化期,不同土壤动物对红桦凋落叶质量损失的贡献率为大型土壤动物(22.7％)＞中型土壤动物(11.9％)＞微型土壤动物(7.9％).季节性冻融期间土壤动物活动是影响川西亚高山森林凋落物分解的重要因素之一.     

薇甘菊入侵对中小型土壤动物群落 结构特征的影响

薇甘菊是菊科假泽兰属的恶性杂草,在我国华南地区已成功入侵并造成严重危害.为了解薇甘菊入侵对土壤动物的影响效应,采用野外样地试验法对广州市火炉山森林公园薇甘菊入侵群落的土壤动物进行了调查.2009年4次采样共获得中小型土壤动物5206头,隶属于4门10纲19类,其中线虫类为优势类群,蜱螨目、弹尾目和轮虫是常见类群.薇甘菊入侵地中小型土壤动物群落结构特征发生了改变,与其他样区相比,入侵区中小型土壤动物的总个体数以及线虫类、蜱螨目的个体数显著增加,但中小型土壤动物类群数的变化不明显;在群落多样性方面,薇甘菊入侵区土壤动物群落的密度-类群指数显著提高,物种丰富度、优势度指数亦有所上升,但差异不明显,而均匀度、Shannon指数趋于下降;在群落相似性方面,薇甘菊入侵区与群落交错区的相似程度较高,与土著植物区的相似程度较低.薇甘菊入侵所引起的局部气候环境、凋落物、根系分泌物与土壤理化性质的变化可能是造成中小型土壤动物群落结构特征改变的主要原因.     

Ground plan and evolution of pterothoracic musculature of moths and butterflies (lepidoptera)

Investigation of the meso- and metathoracic musculature in 62 species of Lepidoptera revealed 40 topographically different muscles, 37 of which presumably belong to the ground plan. The archaic (homoneuran) taxa demonstrate a higher similarity in the musculature of the meso- and metathorax than more advanced (heteroneuran) taxa do. The number of muscles increases with body size but does not depend on the forewing shape or the surface area ratio of the hind and fore wings. Reduction of many muscles occurred repeatedly thus causing similarity between phylogenetically distinct lineages; development of new muscles is rare and occurs mostly as a result of splitting of a muscle into morphologically different parts. Decrease in the number of muscles is accompanied by an increase in their size, more advanced groups generally having relatively larger muscles, especially in the mesothorax. The thoracic anatomy of Lepidoptera is strongly linked with biomechanics of flight and therefore has a relatively low value for phylogenetic analysis, although some characters may be used in reconstruction of phylogeny at the level of subfamilies to superfamilies.     

Efficiency and uncertainties in micro- and mesoscale habitat modelling in large rivers

Habitat modelling has become an increasingly important tool in river sciences to evaluate impacts on running waters and to predict the effects of river restoration in the context of the European Water Framework Directive which aims to reach a good ecological status by 2015. In a scaling framework like the River Scaling Concept, micro- and mesoscale habitat modelling hierarchically integrate point-/local-scale abiotic processes like grain sorting, initiation of sediment transport, bedform development and braiding with biological processes like spawning, daily and seasonal movements, feeding and shifting to refuge habitats. The paper, along with application results, shows that micro- and mesoscale habitat models are complementary especially for large river systems. Overall possibilities, restrictions and future development are discussed. Both rely on dynamic abiotic modelling as a basis as well as on biological data. In future, especially for large rivers, habitat modelling should be addressed on both scales (micro-/meso-) with the main focus on site-specific efficiencies (e.g. minimum efforts) and uncertainties (e.g. transferring suitability indices).     

Cloning, expression and characterization of meso-2,3-butanediol dehydrogenase from Klebsiella pneumoniae

The budC gene encoding the meso-2,3-BDH from Klebsiella pneumoniae XJ-Li was expressed in E. coli BL21 (DE3) pLys. Hypothetical amino acid sequence alignments revealed that the enzyme belongs to the short chain dehydrogenase/reductase family. After purification and refolding, the recombinant enzyme had activities of 218 U/mg for reduction of acetoin and 66 U/mg for oxidation of meso-2,3-butanediol. Highest activities were at pH 8.0 and 9.0 respectively. These are higher than other meso-2,3-butanediol dehydrogenases from K. pneumoniae. The low K (m) value (0.65 mM) for acetoin indicated that the enzyme can easily reduce acetoin to meso-2,3-butanediol. There were no significant activities towards 2R,3R-2,3-butanediol, 1,4-butanediol and 2S,3S-2,3-butanediol, suggesting that the enzyme has a high stereospecificity for the meso-dihydric alcohol.     

玉米-大豆间作和施氮对红壤地中小型土壤动物群落特征的影响

通过2年田间定位试验(2013—2014),利用干漏斗法收集土壤中小型动物,探讨不同种植模式(玉米单作、玉米大豆间作、大豆单作)和施氮(0、150 kg·hm^-2)对红壤土壤动物数量和群落结构的影响.结果表明: 两年取样共捕获土壤中小型动物8349只,分属3门10纲29目,优势类群为蜱螨目和弹尾目.2013年间作和施氮均提高了玉米拔节期土壤动物的平均密度.2014年土壤动物类群数较2013年有明显的增加,施氮条件下的土壤动物平均密度较不施氮有所增加.两年多因素方差分析结果表明,种植模式和生育期对土壤动物平均密度、类群数和多样性指数都无显著影响.但在2014年,施氮显著影响了土壤动物类群数、Simpson指数和密度-类群指数;种植模式与玉米生育期的交互作用显著影响了土壤动物平均密度和类群数,同时对密度-类群和丰富度指数也有显著影响;施氮和生育期的交互作用显著影响了Simpson指数、密度-类群指数和Shannon指数.从两年的土壤动物群落去趋势分析结果来看,红壤地土壤动物群落在种植模式和施氮水平之间均没有明显的差异,群落组成的变化与玉米生育期相关.合理施氮条件下的玉米-大豆间作模式有利于提高红壤地土壤中小型动物平均密度和类群数,保持较好的多样性.     

Arthropod Assemblages in Epiphyte Mats of Costa Rican Cloud Forests

Tropical cloud forests are functionally important ecosystems, but are severely threatened due to deforestation and fragmentation. Epiphyte mats, accumulations of live vegetation and dead organic matter on tree trunks and branches, are a conspicuous component of cloud forests and harbor diverse assemblages of meso- and microarthropods. We compared the morphospecies richness, composition, and abundance of arthropods in epiphyte mats between primary and secondary forests of Monteverde, Costa Rica, and at two nearby replicate sites. Epiphyte mats were thinner and less structurally diverse in secondary forest. We collected ca 36,000 micro- and mesoarthropods from epiphyte mats in the 2-yr study. Whereas arthropod morphospecies richness did not differ among forest types, arthropod abundance was significantly higher in secondary forest due to larger numbers of ants, especially Solenopsis spp. Arthropod assemblages showed a high degree of taxonomic overlap both within and between primary and secondary forests (Jaccard abundance-based similarity = 0.93–0.96). Although characteristics of the arthropod fauna proved to be similar among sites and between forest types, there was a significant temporal effect: arthropod morphospecies richness in epiphyte mats generally was lower in the dry season (February–May), when many taxa probably became dormant or sought shelter against desiccation in deeper portions of mats.     

Upscaling hypotheses on herbivore damage in plants facing environmental stress: Variation among scales and plant enemies in a relict tree

The few existing analyses of broad-scale variation in plant–herbivore interactions are largely exploratory and not based on hypotheses on the effect of varying environmental conditions on the patterns of herbivore damage. However, there are two established hypotheses that relate herbivore damage and environmental stress mostly tested at the within-population level: the Plant Stress Hypothesis (PSH) and the Plant Vigor Hypothesis (PVH). To examine if support for the PSH holds true at broader scales, we tested it at the micro- (among individuals), meso- (between habitats) and macroscale (between geographical regions, Iberia and Macaronesia). We measured plant stress and leaf damage by different natural enemies (chewers, miners and pathogens) in 12 populations across the range of the relict tree Prunus lusitanica. Results regarding the proportion of leaves attacked by any enemy showed no support for the PSH at either micro or mesoscale, observing instead higher damage in less stressed individuals within populations and in high-quality habitats. However, the latter was true exclusively within the Macaronesian region, highlighting the important effect of the type of abiotic stress on plant susceptibility to herbivory. At the macroscale, alternatively, results showed support for the PSH: we observed a higher proportion of leaves attacked in Macaronesia than in Iberia, where plants unexpectedly exhibited greater stress symptoms. Among-scale inconsistencies may respond to the effect of distinct climatic factors governing both plant and herbivore dynamics at large scales, particularly in species with distributional ranges across contrasting climatic regions such as P. lusitanica. Finally, different plant enemies showed different patterns of damage, corroborating the need to study them separately to achieve consistent generalizations of these hypotheses.     

The HIV-poverty thesis re-examined: poverty, wealth or inequality as a social determinant of HIV infection in sub-Saharan Africa?

Although health is generally believed to improve with higher wealth, research on HIV in sub-Saharan Africa has shown otherwise. Whereas researchers and advocates have frequently advanced poverty as a social determinant that can help to explain sub-Saharan Africa's disproportionate burden of HIV infection, recent evidence from population surveys suggests that HIV infection is higher among wealthier individuals. Furthermore, wealthier countries in Africa have experienced the fastest growing epidemics. Some researchers have theorized that inequality in wealth may be more important than absolute wealth in explaining why some countries have higher rates of infection and rapidly increasing epidemics. Studies taking a longitudinal approach have further suggested a dynamic process whereby wealth initially increases risk for HIV acquisition and later becomes protective. Prior studies, conducted exclusively at either the individual or the country level, have neither attempted to disentangle the effects of absolute and relative wealth on HIV infection nor to look simultaneously at different levels of analysis within countries at different stages in their epidemics. The current study used micro-, meso- and macro-level data from Demographic and Health Surveys (DHS) across 170 regions within sixteen countries in sub-Saharan Africa to test the hypothesis that socioeconomic inequality, adjusted for absolute wealth, is associated with greater risk of HIV infection. These analyses reveal that inequality trumps wealth: living in a region with greater inequality in wealth was significantly associated with increased individual risk of HIV infection, net of absolute wealth. The findings also reveal a paradox that supports a dynamic interpretation of epidemic trends: in wealthier regions/countries, individuals with less wealth were more likely to be infected with HIV, whereas in poorer regions/countries, individuals with more wealth were more likely to be infected with HIV. These findings add additional nuance to existing literature on the relationship between HIV and socioeconomic status.     

Emergence in the central nervous system

“Emergence” is an idea that has received much attention in consciousness literature, but it is difficult to find characterizations of that concept which are both specific and useful. I will precisely define and characterize a type of epistemic (“weak”) emergence and show that it is a property of some neural circuits throughout the CNS, on micro-, meso- and macroscopic levels. I will argue that possession of this property can result in profoundly altered neural dynamics on multiple levels in cortex and other systems. I will first describe emergent neural entities (ENEs) abstractly. I will then show how ENEs function specifically and concretely, and demonstrate some implications of this type of emergence for the CNS.     

城市化地区不同生境下中小型土壤动物群落结构特征

2007年5月（春季）、7月（夏季）、11月（秋季）和2008年1月（冬季）,对广州市天河区3种土地利用类型（林地、人工绿地、农田）下6个不同生境的中小型土壤动物群落的结构特征和季节变化进行了调查研究.结果表明：研究区不同生境下中小型土壤动物的水平分布有所不同.调查期间,华南农业大学树木园捕获的中小型土壤动物个体数最多,达1286个,农用地中捕获的个体数较少,以凤凰街农用地中小型土壤动物的个体数和类群数最低;研究区各样地中小型土壤动物的个体数总量有明显的季节消长,由高到低依次为：秋季（1815）>春季（1623）>冬季（1365）>夏季（1276）.聚类与排序结果也说明不同生境样地的中小型土壤动物的群落结构组成随季节不同而呈现出明显的变化规律,同一季节不同生境的中小型土壤动物群落的组成和结构差异与人为干扰程度、土壤环境因素等有关.     

Multi-scale analysis of butterfly diversity in a Mediterranean mountain landscape: mapping and evaluation of community vulnerability

This paper is an attempt to outline a protocol for animal diversity census and evaluation aimed for areas in view of landscape planning of territories of hundred square kilometres and more, that may work utilising different faunal groups and be anyway useful at various scales. Many papers are addressed to elaborate tools for landscape planning starting from biodiversity evaluation and butterflies are often utilised because of their sensitivity to landscape modifications. In this work, the biodiversity evaluation has been performed using three hierarchically linked landscape units at micro-, meso- and macroscale. Being species diversity values often inadequate to define the conservation interest of a landscape portion, more importance has been given to which species compose the species assemblages. A community vulnerability Index was coded and used for evaluating potential consequences of human disturbance on butterfly assemblages. Forty-four year samples were gained by visual census in the Sila Greca, Southern Italy, on an area of approximately 520 square kilometres. During 5 years work, 2,535 specimens and 94 species were recorded, equal to 75.8% of the whole Calabrian fauna. Four vulnerability levels have been established and used for mapping butterfly assemblage vulnerability in the area, starting from a vegetation map. Species richness was found somewhat contradictory at micro-scale, where the community vulnerability Index gives a sounder approach. S diversity gives a more reliable picture of naturalness at meso-scale, a level we identified with the “ecotope”. At this more “geomorphic” scale level, biological functions reflected by butterfly assemblages revealed to be clearly linked to seral processes. Similarity analysis results show that the ecotope species richness, here called “eta-diversity”, could be an useful measure of zoological landscape (faunation) potentialities.     

Causes of Ecosystem Transformation at the End of the Pleistocene: Evidence from Mammal Body-Mass Distributions

Animal body sizes reflect the discontinuous architecture of the landscapes in which they live, and consequently their body-mass distributions are distinctly clumped rather than continuous. This architectural discontinuity is generated by ecological processes that discretely operate over micro-, meso-, and macroscales. Therefore, changes in these important scale-specific processes for a given geographical region over time should be reflected by corresponding changes in faunal body-mass clump patterns. In this study, we utilized this hypothesis to investigate the terminal Pleistocene mammal extinction event. Specifically, we analyzed the body-mass distributions of latest Pleistocene and modern mammal faunas from northern Florida and southern California to determine the nature of any changes in the clump structures of these regions during the Pleistocene–Holocene transition. In both regions, despite their wide geographical separation and faunal distinctiveness, body-mass clumps below the 40-kg level were remarkably stable across the Pleistocene–Holocene transition despite suffering extinctions. Larger clumps, in contrast, were either orderly truncated or completely eliminated rather than chaotically fragmented. Based on these findings, we argue that the terminal Pleistocene mammal extinctions were caused, at least in part, by changes in key mesoscale aspects of the landscape crucial to supporting a diversity of large mammals. Received 23 April 1997; accepted 14 October 1997.     

A thermodynamic model to predict Phanerochaete chrysosporium INA-12 adhesion to various solid carriers in relation to lignin peroxidase production

A thermodynamic model was used in this study to predict the adhesion of Phanerochaete chrysosporium INA-12 as conidiospores or mycelium to various solid carriers. Theoretical predictions were closely reflected by experimental results. Amount of immobilized mycelium was higher for hydrophobic (polypropylene and polyurethane) than for hydrophilic carrier (stainless steel and grey). Lignin peroxidase production was stimulated in the same way. However, better results were obtained with polyurethane than with polypropylene and with grey than with stainless steel. These results were attributed to roughness effects of solid surfaces. Surface morphology characterization showed that the surface roughness parameter R(A) was higher for polyurethane and grey as compared to polypropylene and stainless steel, respectively. On the other hand, polyurethane is not simply rugous; it has an intraparticle porosity as well as a higher total surface area as compared to polypropylene.     

Super-diverse street: a ‘trans-ethnography’ across migrant localities

This paper emerges from an ethnography of the economic and cultural life of Rye Lane, an intensely multi-ethnic street in Peckham, South London. The effects of accelerated migration into London are explored through the reshaping and diversification of its interior, street and city spaces. A ‘trans-ethnography’ is pursued across the compendium of micro-, meso- and macro-urban spaces, without reifying one above the other. The ethnographic stretch across intimate, collective and symbolic city spaces serves to connect how the restrictions and circuits of urban migration have different impacts and expressions in these distinctive but interrelated urban localities. The paper argues for a trans-ethnography that engages within and across a compendium of urban localities, to understand how accelerated migration and urban ‘super-diversity’ transform the contemporary global city.