Ecological Topics Research Articles

Active indole-3-acetic acid biosynthesis by the bacterium Azospirillum brasilense cultured under a biogas atmosphere enables its beneficial association with microalgae.

This study assessed, at the physiological and molecular levels, the effect of biogas on indole-3-acetic acid (IAA) biosynthesis by Azospirillum brasilense as well as the impact of this bacterium during CO2 fixation from biogas by Chlorella vulgaris and Scenedesmus obliquus. IpdC gene expression, IAA production and the growth of A. brasilense cultured under air (control) and biogas (treatment) were evaluated. The results demonstrated that A. brasilense had a better growth capacity and IAA production (105.7±10.3μgml-1 ) when cultured under biogas composed of 25% CO2 +75% methane (CH4 ) with respect to the control (72.4±7.9μgml-1 ), although the ipdC gene expression level was low under the stressful condition generated by biogas. Moreover, this bacterium was able to induce a higher cell density and CO2 fixation rate from biogas by C. vulgaris (0.27±0.08gl-1 d-1 ) and S. obliquus (0.22±0.08gl-1 d-1 ). This study demonstrated that A. brasilense has the capacity to grow and actively maintain its main microalgal growth-promoting mechanism when cultured under biogas and positively influence CO2 fixation from the biogas of C. vulgaris and S. obliquus. These findings broaden research in the field of Azospirillum-microalga interactions and the prevalence of Azospirillum in environmental and ecological topics in addition to supporting the uses of plant growth-promoting bacteria to enhance biotechnological strategies for biogas upgrading.

Hip Hop Naturalism: A Poetics of Afro-pessimism

This article examines the cross-discursive constellation of hip hop studies, ecocriticism, Black Studies, and literary studies. It proposes the notion of “hip hop naturalism” to come to terms with the way in which current U.S.-American rappers express their social ecologies. Taking its cue from scholars such as Imani Perry, Gregory Phipps, and Kecia Driver Thompson, the article argues for the relevance of literary naturalism in contemporary forms of cultural expression: not merely in the audiovisual archives of TV or film, but in hip hop lyricism. Greve scrutinizes how rap has dealt with themes of social heredity, cultural ecology, and structural racial violence by using similar or even identical diction to that of turn-of-the-twentieth-century American literary naturalists. Furthermore, juxtaposing the essentializing aspects of post-Darwinian discourse with those of Afro-pessimism, the article ultimately argues that what Darwinism was to authors like Theodore Dreiser, Jack London, and Frank Norris, Afro-pessimist discourse is to major representatives of contemporary rap, including Mobb Deep, Danny Brown, Earl Sweatshirt, and Kendrick Lamar. The writings of Frank Wilderson III and other scholars within current Black Studies thus figure as a social-philosophical grounding on which the given lyricist might map his or her own take on the lived experience of the black individual in contemporaneity. While racial inequality has always been a central notion within hip hop literature and culture, it is this naturalist bent that renders possible a more thoroughly ecocritical reading of how rap songs both underscore and subvert, with critical defiance, the systemic naturalization of black life as inferior.

China’s Public Firms’ Attitudes towards Environmental Protection Based on Sentiment Analysis and Random Forest Models

In this article, we investigated changes in public firms’ attitudes towards environmental protection in 2018–2021 in China. We crawled the firm–investor Q&A record on the website of East Money, extracted the carbon- and environment-related corpus, and then applied the sentiment analysis method of NLP (natural language processing) to calculate the sentiment weight of each firm-level record to estimate the attitude before and after towards carbon reduction. We found that there were significant changes in firms’ attitudes towards carbon reduction and environmental protection after the COVID-19 pandemic and the implementation of environment-related policies. We also found a heterogeneous effect of the attitude in different industries. In addition, we built several models to examine the relationship between a firm’s carbon reduction attitude and its financial performance. We found that: A goal with consequent specific policies can raise the positive attitudes of firms toward carbon reduction topics; firms’ attitudes toward ecological topics are different from industry to industry, which means that there are different needs and situations in the trend of carbon reduction from industry to industry. COVID-19 influenced firms’ attitudes toward carbon reduction and environmental protection, calling back the classic dilemma or trilemma of economic growth, carbon reduction, and energy consumption or, perhaps, epidemic control today. The stock situation also influenced the attitude toward environmental protection.

Comparative Research on Typical Measure Methods of the Carbon Sequestration Benefits of Urban Trees Based on the UAV and the 3D Laser: Evidence from Shanghai, China

The Carbon Sequestration Benefits (CSB) of vegetation and forest have received more and more attention with the increase in CO2 density in the atmosphere. The evaluation of the CSB of existing vegetation and forest has also become one of the important research topics in urban ecology. In the existing research, the evaluation of CSB methods can be categorized into a two-dimension index and three-dimension index. The two-dimension index mainly focuses on leaf area method and leaf area index method. Additionally, the three-dimension index mostly focuses on the Three-Dimension Green Quantity (3DGQ) method which further includes Approximate Geometry Model (AGM), Point Cloud (PC) method using 3D laser, and Point Cloud Convex Hull Slicing (PCCHS) method, etc. In this paper, we take Shanghai as the study area, and address the top 15 species with each species having 30 trees of the same age from Shanghai to calculate the average annual CSB of the 15 species using the two-dimension index and three-dimension index. Through this, we analyze the difference of the same species in different indexes in the same categories and in different categories. The research results provide a research basis for the in-depth exploration of the three-dimensional spatial pattern of urban green space and ecological benefit evaluation.

A framework and case study to systematically identify long‐term insect abundance and diversity datasets

AbstractBiodiversity is in crisis, and insects are no exception. To understand insect population and community trends globally, it is necessary to identify and synthesize diverse datasets representing different taxa, regions, and habitats. The relevant literature is, however, vast and challenging to aggregate. The Entomological Global Evidence Map (EntoGEM) project is a systematic effort to search for and catalogue studies with long‐term data that can be used to understand changes in insect abundance and diversity. Here, we present the overall EntoGEM framework and results of the first completed subproject of the systematic map, which compiled sources of information about changes in dragonfly and damselfly (Odonata) occurrence, abundance, biomass, distribution, and diversity. We identified 45 multi‐year odonate datasets, including 10 studies with data that span more than 10 years. If data from each study could be gathered or extracted, these studies could contribute to analyses of long‐term population trends of this important group of indicator insects. The methods developed to support the EntoGEM project, and its framework for synthesizing a vast literature, have the potential to be applied not only to other broad topics in ecology and conservation, but also to other areas of research where data are widely distributed.

Intermediate dispersal hypothesis of species diversity: New insights

AbstractThe origin and patterns of species diversity are fundamental themes in ecology and evolutionary biology. Insular systems play an important role in biogeography, and the species richness within an insular system has classically been considered as determined by the balance between the rate of speciation plus net migration and the rate of species extinction. A recent wave of studies integrating comprehensive phenotypic, phylogenetic, and environmental data is accumulating additional macroevolutionary insights at unprecedented scales. In this review, I summarize and discuss the hypothesis that intermediate dispersal ability leads to clades with high species diversity by recurrent speciation events (referred to as the intermediate dispersal hypothesis, IDH). Although some recent empirical and theoretical studies have supported the IDH, further integration of other ecological and evolutionary concepts spanning different timescales is needed to resolve long‐standing debates about the non‐linear relationship between diversification and organismal dispersal ability. This paper presents a framework for future studies that intend to test the IDH; I organize the factors that should be taken into account, including the indices for quantifying dispersal ability and species diversification, and methods of taxon sampling. The IDH requires more attention and could be used to unveil the diversity of extant species and how dispersal ability affects rates of speciation and extinction.

A replicated study on the response of spider assemblages to regional and local processes

AbstractUnderstanding species richness variation among local communities is one of the central topics in ecology, but the complex interplay of regional processes, environmental filtering, and local processes hampers generalization on the importance of different processes. Here, we aim to unravel drivers of spider community assembly in temperate forests by analyzing two independent data sets covering gradients in elevation and forest succession. We test the following four hypotheses: (H1) spider assemblages within a region are limited by dispersal, (H2) local environment has a dominant influence on species composition and (H3) resources, and (H4) biotic interactions both affect species richness patterns. In a comprehensive approach, we studied species richness, abundance, taxonomic composition, and trait‐phylogenetic dissimilarity of assemblages. The decrease in taxonomic similarity with increasing spatial distance was very weak, failing to support H1. Functional clustering of species in general and with canopy openness strongly supported H2. Moreover, this hypothesis was supported by a positive correlation between environmental and taxonomic similarity and by an increase in abundance with canopy openness. Resource determination of species richness (H3) could be confirmed only by the decrease of species richness with canopy cover. Finally, decreasing species richness with functional clustering indicating effects of biotic interactions (H4) could only be found in one analysis and only in one data set. In conclusion, our findings indicate that spider assemblages within a region are mainly determined by local environmental conditions, while resource availability, biotic interactions and dispersal play a minor role. Our approach shows that both the analysis of different aspects of species diversity and replication of community studies are necessary to identify the complex interplay of processes forming local assemblages.

Науковий vs розважальний контент в українському екологічному теледискурсі: проблеми та особливості

The article explores the coverage of topics of ecology in the news programs of Ukrainian television. Based on the study of news releases on the all-Ukrainian TV channel “1+1” and the specialized TV channel “ECO TV”, it emphasizes the importance of media discourse for the promotion of ecological knowledge in order to form a general environmental culture, environmental awareness and pro-ecological behavior. In general, there is a segment of scientific content in the modern Ukrainian environmental discourse, but its volume is insignificant compared to entertainment. Topics of ecology require more attention, as well as greater efforts of national and specialized media for the quantitative and qualitative development of eco-journalism, improving scientific and ecological literacy of citizens. The relevance of the study is determined by the fact that the media significantly expand the public understanding of ecology as an environmental science and draw public attention to environmental issues. Today’s frequent environmental disasters and catastrophes, rising levels of environmental pollution resulted in enhanced awareness of the need to save resources, create environmentally friendly, low-waste and waste-free technologies, reduce emissions and, most importantly, in adverting more public attention to environmental media discourse. The media plays an important role in molding public opinion on the environment and dissemination of ecological knowledge to a mass audience. Therefore, at present, it is more necessary than ever before to present environmental issues in the mass media and form a high environmental awareness of the public.

Ecological Rhetoric: Topics of Newspaper Headlines

The media perform not only the function of information but also of ecological education: it forms the ecological identity of its target audience. The media help to present the topics of ecology, climate change, and sustainable development for the public in a more understandable and persuasive language. Also, the discourse of ecology in the media is bidirectional: it is created not only by the representatives of science and social actors but also by the media themselves, which form the concept of ecology in their desired direction. Rhetorical analysis of ecological discourse allows us to identify the components of this ecological worldview and to elucidate their mechanisms of persuasion and proof. The present research was focused on the logical and rhetorical topoi in the headlines of articles on ecology. The aim of this research was to identify and analyse ecological topics in headlines. The research material was analysed using the method of rhetorical discourse analysis, which allowed us to distinguish and define the categories of the research object. The method of rhetorical analysis was combined with critical discourse analysis that investigates real cases of social interaction in authentic media-broadcast persuasive discourse and their mechanisms of persuasion. The analysis of the headlines helped to identify the dominant logical topics, the recurring themes: sustainable development and consumption, climate change, environmental protection. The logical topics in the headlines is verbalised by a role model, example, cause and consequence, and novelty topoi.

Niche Variation in Endemic Lilium pomponium on a Wide Altitudinal Gradient in the Maritime Alps.

The relationship between altitudinal and ecological gradients has long been a dominant theme in plant ecology; moreover, how species respond to climate change has renewed this interest. Mediterranean mountains are often hotspots of endemism, and some endemic species have local distributions that span different climatic belts; hence, local variations in topography and fine-scaled niche conditions may play crucial roles in their persistence along such gradients. Studies of the fine-scaled niche are, however, very rare; most studies involve broad-scale variations in climatic parameters. The Turban lily, Lilium pomponium L. is endemic to the Maritime and Ligurian Alps, where it occurs across a wide altitudinal gradient. Previous work has shown no link between climatic marginality and geographic range limits on morphological traits and genetic variability; however, possible variations of local topographic and ecological parameters have not yet been examined. The objective of this paper is to characterise local ecological niche conditions of L. pomponium populations in the different bioclimatic zones it occupies along the altitudinal gradient. The species occurs in four main types of microecological niches. One of these niche types, with a high mineral cover, is the most abundant—type 2: it was detected in 39% of sampled quadrats and occurs across the whole bioclimatic gradient. Other niche types are more limited to subsections of the gradient: type 3 (in 19% of sampled quadrats) is restricted to high-altitude sites (>1070 m.a.s.l.) and is characterised by high vegetation and litter cover; type 4 (26%) corresponds to more forested habitats on substrates with low water retention capacities, in more inland zones close to the centre of L. pomponium distribution and across a range of altitudes; and type 1 (16% of quadrat) only occurs in the Mediterranean part of the gradient, close to distribution limits in pockets of soil among large blocks of rocks, mainly found at mid-altitudes. Despite heterogeneity in the spatial locations of niche types, there is no correspondence between ecological gradients and the distribution limits of this species. Knowledge of the fine-scaled ecological conditions that determine niche types is thus essential for conservation management of the habitats of this species and for the exploration of its possible response to ongoing climate change.

How Phylogenetics Can Elucidate the Chemical Ecology of Poison Frogs and Their Arthropod Prey

The sequestration by neotropical poison frogs (Dendrobatidae) of an amazing array of defensive alkaloids from oribatid soil mites has motivated an exciting research theme in chemical ecology, but the details of mite-to-frog transfer remain hidden. To address this, McGugan et al. (2016, Journal of Chemical Ecology 42:537-551) used the little devil poison frog (Oophaga sylvatica) and attempted to simultaneously characterize the prey mite alkaloids, the predator skin alkaloids, and identify the mites using DNA sequences. Heethoff et al. (2016, Journal of Chemical Ecology 42:841-844) argued that none of the mite families to which McGugan et al. allocated the prey was thought to possess alkaloids. Heethoff et al. concluded from analyses including additional sequences that the mite species were unlikely to be close relatives of the defended mites. We re-examine this by applying more appropriate phylogenetic methods to broader and denser taxonomic samples of mite sequences using the same gene (CO1). We found, over trees based on CO1 datasets, only weak support (except in one case) for branches critical to connecting the evolution of alkaloid sequestration with the phylogeny of mites. In contrast, a well-supported analysis of the 18S ribosomal gene suggests at least two independent evolutionary origins of oribatid alkaloids. We point out impediments in the promising research agenda, namely a paucity of genetic, chemical, and taxonomic information, and suggest how phylogenetics can elucidate at a broader level the evolution of chemical defense in prey arthropods, sequestration by predators, and the impact of alkaloids on higher-order trophic interactions.

Rhizosphere bacteriome structure and functions

Microbial composition and functions in the rhizosphere—an important microbial hotspot—are among the most fascinating yet elusive topics in microbial ecology. We used 557 pairs of published 16S rDNA amplicon sequences from the bulk soils and rhizosphere in different ecosystems around the world to generalize bacterial characteristics with respect to community diversity, composition, and functions. The rhizosphere selects microorganisms from bulk soil to function as a seed bank, reducing microbial diversity. The rhizosphere is enriched in Bacteroidetes, Proteobacteria, and other copiotrophs. Highly modular but unstable bacterial networks in the rhizosphere (common for r-strategists) reflect the interactions and adaptations of microorganisms to dynamic conditions. Dormancy strategies in the rhizosphere are dominated by toxin–antitoxin systems, while sporulation is common in bulk soils. Functional predictions showed that genes involved in organic compound conversion, nitrogen fixation, and denitrification were strongly enriched in the rhizosphere (11–182%), while genes involved in nitrification were strongly depleted.

Environmental structure impacts microbial composition and secondary metabolism

Determining the drivers of microbial community assembly is a central theme of microbial ecology, and chemical ecologists seek to characterize how secondary metabolites mediate these assembly patterns. Environmental structure affects how communities assemble and what metabolic pathways aid in that assembly. Here, we bridged these two perspectives by addressing the chemical drivers of community assembly within a spatially structured landscape with varying oxygen availability. We hypothesized that structured environments would favor higher microbial diversity and metabolite diversity. We anticipated that the production of a compound would be more advantageous in a structured environment (less mixing) compared to an unstructured environment (more mixing), where the molecule would have a diminished local effect. We observed this to be partially true in our experiments: structured environments had similar microbial diversity compared to unstructured environments but differed significantly in the metabolites produced. We also found that structured environments selected for communities with higher evenness, rather than communities with higher richness. This supports the idea that when characterizing the drivers of community assembly, it matters less about who is there and more about what they are doing. Overall, these data contribute to a growing effort to approach microbial community assembly with interdisciplinary tools and perspectives.

The Awakening of Human Nature—On Tim Winton’s Shallows

Shallows is one of the award-winning works of Tim Winton. Winton is a famous contemporary Australian writer. At present, the study of this novel by scholars and experts is limited to the interpretation of the ecological theme. The analysis of this paper is based on Shallows, using humanism nature theory to analyze the characters in the novel, the actions the dialogue and the mind of people to reveal the awakening of human nature. The awakening is the key to solve the imbalance between current human and natural ecological. Only when man and nature live in harmony, human beings can survive and develop for a long time, which is also beneficial to the self-improvement in the moral level.

Assessing Railway Landscape by AHP Process with GIS: A Study of the Yunnan-Vietnam Railway

Landscape quality is a crucial factor for the heritage attractiveness of tourism, allowing tourists to experience both natural and cultural aspects along railway journeys. Moreover, railway landscape is a comprehensive system that defines the landscape observed and perceived by passengers and is characterized by the diversity and continuity of the train’s movement. Yunnan-Vietnam railway (YVR) heritage is the research object of this research, whose area encompasses various landscape types and heritage sites, providing great landscape enjoyment. Currently, the assessment methods specifically for railway landscape have been discussed less than for other landscape types, especially for a series of large linear sites like the YVR. To evaluate the value of railway heritage landscape along the railway, this paper proposes a methodology combining the Analytic Hierarchy Process (AHP), Delphi method, and GIS as an integrated spatial assessment. Creatively, this paper seeks to: (1) discuss the relationship between railway and landscape; (2) build a comprehensive evaluation system for the railway heritage landscape, covering the topics of history, tourism, ecology, heritage, social-culture, and visual quality; (3) quantify the landscape value of the YVR areas. Thus, the results of this research can be useful to future urban planning, development, and policymaking.

Crop species and year affect soil-dwelling Collembola and Acari more strongly than fertilisation regime in an arable field

Drivers of soil-dwelling microarthropods represent one of the most addressed topics in soil ecology, and diverse results have been reported in the literature. In the present study, an extremely long-term fertilised monoculture system provided a special opportunity to investigate the drivers of soil-dwelling springtail and mite assemblages. The cropping system included wheat and maize monoculture and biculture and was managed with mineral and organic fertilisers for over 50 years. Soil samples were collected two times a year for two years from four blocks. Soil-dwelling mite groups and springtail orders were identified and analysed based on soil characteristics and compared amongst different treatments to reveal the drivers. In addition, oribatid mites and springtails were identified at the species level and analysed. The most important parameters were ‘crop species’ and ‘study year’. Most Collembola and Acari groups were more abundant in wheat plantations, and there were yearly variations within different mite and collembolan groups. Fertilisation appeared to produce no effect on microarthropod assemblages; however, soil pH and phosphate concentration differed according to fertilisation treatment. Overall, the four blocks at the study site effectively reflected the spatial patterns of oribatid species. Specifically, the dominant collembolan species exhibited similar patterns to the major collembolan orders, whereas oribatid species presented different patterns within Oribatida. The studied special agricultural system helped reveal important drivers of soil-dwelling Collembola and Acari, and these soil-dwelling microarthropod assemblages are affected more strongly by ‘crop species’ and ‘study year’ than by long-term fertilisation regime.

Random placement models explain species richness and dissimilarity of frog assemblages within Atlantic Forest fragments.

Understanding the effects of random versus niche-based processes on biodiversity patterns is a central theme in ecology, and an important tool for predicting effects of habitat loss and fragmentation on biodiversity. We investigated the predictive power of random processes to explain species richness and species dissimilarity of amphibian assemblages in a fragmented tropical landscape of the Atlantic Forest of South America. We analyzed a large database of amphibian abundance and occupancy, sampled in 21 forest fragments ranging in size from 1.9 to 619ha. We compared observed species richness and species dissimilarity with the outcomes of two null (random placement) models: 1- the traditional Coleman's area-based model and 2- an abundance-based model (based on the number of individuals observed in each fragment). We applied these models for all species combined, and separately for forest-dependent and habitat-generalist species. The abundance-based model fitted the observed species richness data better than the area-based model for all species, forest-dependent species, and generalist species. The area-based and the abundance-based models were also able to significantly explain species dissimilarity for all species and for generalists, but not for forest dependent species. The traditional area-based model assigned too many individuals to large fragments, thus failing to accurately explain species richness within patches across the landscape. Although niche-based processes may be important to structuring the regional pool of species in fragmented landscapes, our results suggest that part of the variation in species richness and species dissimilarity can be successfully explained by random placement models, especially for generalist species. Evaluating which factors cause variation in the number of individuals among patches should be a focus in future studies aiming to understand biodiversity patterns in fragmented landscapes.

Rare soil bacteria are more responsive in desertification restoration than abundant bacteria.

Soil microbes play key roles in ecosystem functions, especially in the recovery of ecosystems from disturbance, and exploring community assembly under changing environments has long been a central theme in microbial ecology. The response of abundant and rare bacteria in desertified land to restoration is still unclear. Here, we investigated the effects of vegetation restoration on the assemblage patterns of abundant and rare bacteria in soil across the four sandy lands (Hulunbeir, Horqin, Otindag, and Mu Us) in northern China. Our results revealed that abundant bacteria maintained a relatively stable state under restoration, whereas rare taxa were more responsive, indicating the higher resilience of the rare community to change. Our network analysis also showed that restoration promoted destabilizing properties in rare, but not in abundant, bacterial co-occurrence networks in soil. Environmental selection played a key role in abundant and rare community assembly under restoration. Of the two, the rare subcommunity was mainly affected by environmental filtering. The variations in the abundant and rare communities at the sampling sites under restoration were controlled mainly by plant species richness, and stronger effects were observed in the rare taxa. Overall, these results provide new insight into the mechanisms controlling bacterial community assembly in response to vegetation restoration.

Modification and coupled use of technologies are an essential envisioned need for bioaerosol study – An emerging public health concern

The airborne microbiome is one of the relevant topics in ecology, biogeochemistry, environment, and human health. Bioaerosols are ubiquitous air pollutants that play a vital role in the linking of the ecosystem with the biosphere, atmosphere, climate, and public health. However, the sources, abundance, composition, properties, and atmospheric transport mechanisms of bioaerosols are not clearly understood. To screen the effects of climate change on aerosol microbial composition and its consequences for human health, it is first essential to develop standards that recognize the existing microbial components and how they vary naturally. Bioaerosol particles can be considered an information-rich unit comprising diverse cellular and protein materials emitted by humans, animals, and plants. Hence, no single standard technique can satisfactorily extract the required information about bioaerosols. To account for these issues, metagenomics, mass spectrometry, and biological and chemical analyses can be combined with climatic studies to understand the physical and biological relationships among bioaerosols. This can be achieved by strengthening interdisciplinary teamwork in biology, chemistry, earth science, and life sciences and by sharing knowledge and expertise globally. Thus, the coupled use of various advanced analytical approaches is the ultimate key to opening up the biological treasure that lies in the environment.

Biota-mediated carbon cycling-A synthesis of biotic-interaction controls on blue carbon.

Research into biotic interactions has been a core theme of ecology for over a century. However, despite the obvious role that biota play in the global carbon cycle, the effects of biotic interactions on carbon pools and fluxes are poorly understood. Here we develop a conceptual framework that illustrates the importance of biotic interactions in regulating carbon cycling based on a literature review and a quantitative synthesis by means of meta-analysis. Our study focuses on blue carbon ecosystems-vegetated coastal ecosystems that function as the most effective long-term CO2 sinks of the biosphere. We demonstrate that a multitude of mutualistic, competitive and consumer-resource interactions between plants, animals and microbiota exert strong effects on carbon cycling across various spatial scales ranging from the rhizosphere to the landscape scale. Climate change-sensitive abiotic factors modulate the strength of biotic-interaction effects on carbon fluxes, suggesting that the importance of biota-mediated carbon cycling will change under future climatic conditions. Strong effects of biotic interactions on carbon cycling imply that biosphere-climate feedbacks may not be sufficiently represented in current Earth system models. Inclusion of new functional groups in these models, and new approaches to simplify species interactions, may thus improve the predictions of biotic effects on the global climate.