scholarly journals Rapid functional traits turnover in boreal dragonfly communities (Odonata)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marina Schmidt Dalzochio ◽  
Eduardo Périco ◽  
Norton Dametto ◽  
Göran Sahlén

Abstract All natural populations show fluctuations in space or time. This is fundamental for the maintenance of biodiversity, as it allows species to coexist. Long-term ecological studies are rare, mainly due to logistics, but studies like the one presented below recognize the dimensionality of temporal change and the ecological processes that lead to shifts in community composition over time. Here, we used three sampling occasions from a dataset spanning 20 years where dragonflies in central Sweden were monitored. Our aim was to investigate how the prevalence of ecological and biological species traits varied over time measured as Community-level Weighted Means of trait values (CWM). Most CWM values varied significantly between years. Most of the traits changed between the second and the last sampling occasion, but not between the two first ones. These changes could be linked to major changes in species abundance. Our work indicates that fundamental shifts in community structure can occur over a short time, providing environmental drivers act on species turnover. In our case, Climate change and pH levels in lakes are most likely the most important factors.

2021 ◽  
Author(s):  
Haijun Yuan ◽  
Weizhen Zhang ◽  
Huaqun Yin ◽  
Runyu Zhang ◽  
Jianjun Wang

Abstract Microbial beta diversity has been recently studied along the water depth in aquatic ecosystems, however its turnover and nestedness components remain elusive especially for multiple taxonomic groups. Based on the beta diversity partitioning developed by Baselga and Local Contributions to Beta Diversity (LCBD) partitioning by Legendre, we examined the water-depth variations in beta diversity components of bacteria, archaea and fungi in surface sediments of Hulun Lake, a semi-arid lake in northern China, and further explored the relative importance of environmental drivers underlying their patterns. We found that the relative abundances of Proteobacteria, Chloroflexi, Euryarchaeota and Rozellomycota increased towards deep water, while Acidobacteria, Parvarchaeota and Chytridiomycota decreased. For bacteria and archaea, there were significant (P < 0.05) decreasing water-depth patterns for LCBD and LCBDRepl (i.e., species replacement), while increasing patterns for total beta diversity and turnover, implying that total beta diversity and LCBD were dominated by species turnover or LCBDRepl. Further, bacteria showed a strong correlation with archaea regarding LCBD, total beta diversity and turnover. Such parallel patterns among bacteria and archaea were underpinned by similar ecological processes like environmental selection. Total beta diversity and turnover were largely affected by sediment total nitrogen, while LCBD and LCBDRepl were mainly constrained by water NO2−-N and NO3−-N. For fungal community variation, no significant patterns were observed, which may be due to different drivers like water nitrogen or phosphorus. Taken together, our findings provide compelling evidences for disentangling the underlying mechanisms of community variation in multiple aquatic microbial taxonomic groups.


2021 ◽  
Vol 8 ◽  
Author(s):  
Alexandre Muller ◽  
Camille Poitrimol ◽  
Flávia L. D. Nunes ◽  
Aurélien Boyé ◽  
Amelia Curd ◽  
...  

Reef-building species are recognized as having an important ecological role and as generally enhancing the diversity of benthic organisms in marine habitats. However, although these ecosystem engineers have a facilitating role for some species, they may exclude or compete with others. The honeycomb worm Sabellaria alveolata (Linnaeus, 1767) is an important foundation species, commonly found from northwest Ireland to northern Mauritania, whose reef structures increase the physical complexity of the marine benthos, supporting high levels of biodiversity. Local patterns and regional differences in taxonomic and functional diversity were examined in honeycomb worm reefs from 10 sites along the northeastern Atlantic to explore variation in diversity across biogeographic regions and the potential effects of environmental drivers. While taxonomic composition varied across the study sites, levels of diversity remained relatively constant along the European coast. Assemblages showed high levels of species turnover compared to differences in richness, which varied primarily in response to sea surface temperatures and sediment content, the latter suggesting that local characteristics of the reef had a greater effect on community composition than the density of the engineering species. In contrast, the functional composition of assemblages was similar regardless of taxonomic composition or biogeography, with five functional groups being observed in all sites and only small differences in abundance in these groups being detected. Functional groups represented primarily filter-feeders and deposit-feeders, with the notable absence of herbivores, indicating that the reefs may act as biological filters for some species from the local pool of organisms. Redundancy was observed within functional groups that may indicate that honeycomb worm reefs can offer similar niche properties to its associated assemblages across varying environmental conditions. These results highlight the advantages of comparing taxonomic and functional metrics, which allow identification of a number of ecological processes that structure marine communities.


2020 ◽  
Vol 65 (4) ◽  
pp. 401-422
Author(s):  
Estelle Variot
Keyword(s):  
The One ◽  

"Etymological, Lexical and Semantic Correspondences in the Process of Feminization of Professional Names, Trades and Activities in French and Romanian Societies. The feminization of thought represented by language and of its varieties in the Roman World has allowed to highlight some convergences that come from a common linguistic heritage, often from Greek and Latin and some hesitation about adapting society to its realities. The feminization of some words which comes from an ancient process illustrates on the one hand the potential of the language and on the other hand some constraints sometimes linked to the society itself, which creates transitional periods, between matching grammatical correction and the evolution of linguistic uses over time. The possibilities of lexical enrichment (internal creation or loan) show the means available in French and Romanian and some convergences in the area of derivation, of lexical units and their etymologies. The grammatical perspective and word constructing methods make it possible to give keys for the feminization of names of trades or professions. Likewise, recording entries in the lexicon, their evolution, their assimilation or sometimes their forgetfulness, for the benefit of new constructions highlight the existence of objective and subjective criteria which teach us a lot about society as a whole. Keywords: feminization of professions, internal and external enrichment, suffixal match, use of words, grammar, lexicon, French and Romanian."


2019 ◽  
Vol 95 (4) ◽  
pp. 517-530
Author(s):  
Diana Lohwasser

Abstract The Educator as a Manager. A Critical View In the following article tasks and motifs of the educator as manager are described. It is clear that there are other educator metaphors and associated behaviors. To some extent, the actions of the different educator metaphors overlap, but they differ in their purpose and perspective on the educational process and the person to be educated. First, a short time diagnosis is made, which describes the context of this metaphor of the educator as manager. Subsequently, on the one hand, the various motifs, tasks and objectives of an educator as manager are discussed. On the other hand, it is asked if it is possible in the current discourse to take a different perspective on the educational process.


Author(s):  
Christopher Tuck

This chapter charts the key developments in European land warfare since 1900. On the one hand, it is possible to identify overarching explanatory ideas, metanarratives, that can be used to identify continuities in development over time across Europe’s armies. These include the concept of ‘modern system’ land warfare and the ‘transformation paradigm’. However, as this chapter also shows, these two points of continuity do not mean either that European armies are homogenous, or that their conceptual assumptions are uncontested. European land warfare remains a heterogeneous phenomenon, shaped by the variety in national contexts and by contending debates on how appropriate Europe’s armies are to the actual challenges of contemporary and future armed conflict.


The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3929
Author(s):  
Han-Yun Chen ◽  
Ching-Hung Lee

This study discusses convolutional neural networks (CNNs) for vibration signals analysis, including applications in machining surface roughness estimation, bearing faults diagnosis, and tool wear detection. The one-dimensional CNNs (1DCNN) and two-dimensional CNNs (2DCNN) are applied for regression and classification applications using different types of inputs, e.g., raw signals, and time-frequency spectra images by short time Fourier transform. In the application of regression and the estimation of machining surface roughness, the 1DCNN is utilized and the corresponding CNN structure (hyper parameters) optimization is proposed by using uniform experimental design (UED), neural network, multiple regression, and particle swarm optimization. It demonstrates the effectiveness of the proposed approach to obtain a structure with better performance. In applications of classification, bearing faults and tool wear classification are carried out by vibration signals analysis and CNN. Finally, the experimental results are shown to demonstrate the effectiveness and performance of our approach.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jingxia Lin

AbstractTypological shift in lexicalizing motion events has hitherto been observed cross-linguistically. While over time, Chinese has shown a shift from a dominantly verb-framed language in Old Chinese to a strongly satellite-framed language in Modern Standard Mandarin, this study presents the Chinese dialect Wenzhou, which has taken a step further than Standard Mandarin and other Chinese dialects in becoming a thoroughly satellite-framed language. On the one hand, Wenzhou strongly disfavors the verb-framed pattern. Wenzhou not only has no prototypical path verbs, but also its path satellites are highly deverbalized. On the other hand, Wenzhou strongly prefers the satellite-framed pattern, to the extent that it very frequently adopts a neutral motion verb to head motion expressions so that path can be expressed via satellites and the satellite-framed pattern can be syntactically maintained. The findings of this study are of interest to intra-linguistic, diachronic and cross-linguistic studies of the variation in encoding motion events.


2021 ◽  
pp. 016344372110227
Author(s):  
Yingzi Wang ◽  
Thoralf Klein

This paper examines the changes and continuities in TV representations of Chinese Communist Party’s revolutionary history and interprets them within the broader context of China’s political, economic and cultural transformations since the 1990s. Drawing on a comparative analysis of three state-sponsored TV dramas produced between the late 1990s and mid-2010s, it traces how the state-sanctioned revolutionary narratives have changed over time in response to the Party’s propaganda imperatives on the one hand, and to the market-oriented production environment on the other. The paper argues that while recent TV productions in the new century have made increasing concessions to audience taste by adopting visually stimulating depictions and introducing fictional characters as points of identification for the audience, the revolutionary narratives were still aligned with the Party’s propaganda agenda at different times. This shows the ongoing competition between ideological and commercial interests in Chinese TV production during the era of market reforms.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ann Sophie K. Löhde ◽  
Giovanna Campopiano ◽  
Andrea Calabrò

PurposeChallenging the static view of family business governance, we propose a model of owner–manager relationships derived from the configurational analysis of managerial behavior and change in governance structure.Design/methodology/approachStemming from social exchange theory and building on the 4C model proposed by Miller and Le Breton-Miller (2005), we consider the evolving owner–manager relationship in four main configurations. On the one hand, we account for family businesses shifting from a generalized to a restricted exchange system, and vice versa, according to whether a family manager misbehaves in a stewardship-oriented governance structure or a nonfamily manager succeeds in building a trusting relationship in an agency-oriented governance structure. On the other hand, we consider that family firms will strengthen a generalized exchange system, rather than a restricted one, according to whether a family manager contributes to the stewardship-oriented culture in the business or a nonfamily manager proves to be driven by extrinsic rewards. Four scenarios are analyzed in terms of the managerial behavior and governance structure that characterize the phases of the relationship between owners and managers.FindingsVarious factors trigger managerial behavior, making the firm deviate from or further build on what is assumed by stewardship and agency theories (i.e. proorganizational versus opportunistic behavior, respectively), which determine the governance structure over time. Workplace deviance, asymmetric altruism and patriarchy on the one hand, and proorganizational behavior, relationship building and long-term commitment on the other, are found to determine how the manager behaves and thus characterize the owner's reactions in terms of governance mechanisms. This enables us to present a dynamic view of governance structures, which adapt to the actual attitudes and behaviors of employed managers.Research limitations/implicationsAs time is a relevant dimension affecting individual behavior and triggering change in an organization, one must consider family business governance as being dynamic in nature. Moreover, it is not family membership that determines the most appropriate governance structure but the owner–manager relationship that evolves over time, thus contributing to the 4C model.Originality/valueThe proposed model integrates social exchange theory and the 4C model to predict changes in governance structure, as summarized in the final framework we propose.


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