scholarly journals The Joint Contributions of Environmental Filtering and Spatial Processes to Macroinvertebrate Metacommunity Dynamics in the Alpine Stream Environment of Baima Snow Mountain, Southwest China

Diversity ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 28
Author(s):  
Muhammad Farooq ◽  
Xianfu Li ◽  
Zhengfei Li ◽  
Ronglong Yang ◽  
Zhen Tian ◽  
...  
Keyword(s):  
Community Ecology ◽  
Community Assembly ◽  
Temporal Dynamics ◽  
Explanatory Power ◽  
Environmental Filtering ◽  
Ecological Factors ◽  
Spatial Processes ◽  
Relative Significance ◽  
Alpine Stream ◽  
Over Time

While macroinvertebrates are extensively investigated in many river ecosystems, meta-community ecology perspectives in alpine streams are very limited. We assessed the role of ecological factors and temporal dynamics in the macroinvertebrate meta-community assembly of an alpine stream situated in a dry-hot valley of Baima Snow Mountain, China. We found that spatial structuring and environmental filtering jointly drive the structure of macroinvertebrate meta-community, with relative contributions to the variance in community composition changing over time. RDA ordination and variation partitioning indicate that environmental variables are the most important predictors of community organization in most scenarios, whereas spatial determinants also play a significant role. Moreover, the explanatory power, identity, and the relative significance of ecological factors change over time. Particularly, in the years 2018 and 2019, stronger environmental filtering was found shaping community assembly, suggesting that deterministic mechanisms predominated in driving community dynamics. However, spatial factors had a stronger predictive power on meta-community structures in 2017, implying conspicuous dispersal mechanisms which may be owing to increased connectivity amongst sites. Thereby, we inferred that the alpine stream macroinvertebrate metacommunity composition can be regulated by the interaction of both spatial processes and environmental filtering, with relative contributions varying over time. Based on these findings, we suggest that community ecology studies in aquatic systems should be designed beyond single snapshot investigations.

scholarly journals The joint contributions of environmental filtering and spatial processes to macroinvertebrate metacommunity dynamics in the alpine stream environment of Baima Snow Mountain, Southwest China

2021 ◽  
Author(s):  
Muhammad Farooq ◽  
Xianfu Li ◽  
Zhengfei Li ◽  
Ronglong Yang ◽  
Zhen Tian ◽  
...  
Keyword(s):  
Community Ecology ◽  
Community Composition ◽  
Community Assembly ◽  
Environmental Filtering ◽  
Mountain Stream ◽  
High Mountain ◽  
Spatial Processes ◽  
Relative Significance ◽  
Alpine Stream ◽  
Over Time

As a rapidly growing field of community ecology, the study of meta-communities provides an effective framework to unravel community assembly mechanisms by focusing on the relative contributions of environmental screening and spatial processes. While macroinvertebrates have been extensively investigated in many river ecosystems, meta-community ecology perspectives in high mountain stream networks are very limited. In this study, we assessed the role of ecological determinants and temporal dynamics in the macroinvertebrate meta-community assembly of an alpine stream situated in a dry-hot valley of Baima Snow Mountain, Northwest Yunnan. Our results show significant differences in the macroinvertebrate community composition across time periods. Spatial structuring and environmental filtering jointly drive the configuration of macroinvertebrate meta-community, with relative contributions to the variance in community composition varying over time. Redundancy Analysis (RDA) and variation partitioning indicate that environmental variables are the most important predictors of community organization in most scenarios, whereas spatial determinants also play a significant role. Moreover, the explanatory power, identity, and the relative significance of ecological indicators change over time. Particularly, in the years 2018 and 2019, stronger environmental filtering was found shaping community assembly, suggesting that deterministic mechanisms predominated in driving community dynamics in such a specific environment of the stream. However, spatial factors had a stronger predictive power on meta-community structures in 2017, implying conspicuous dispersal mechanisms which may be owing to increased connectivity amongst locations. Thereby, we inferred that the stream macroinvertebrate metacommunity composition can be regulated by the interaction of both spatial processes and environmental filtering, with relative contributions varying over time. Based on these findings, we suggest that community ecology studies in aquatic systems should be designed beyond single snapshot investigations.

scholarly journals Ecosystem size-induced environmental fluctuations affect the temporal dynamics of community assembly mechanisms

2022 ◽  
Author(s):  
Raven L Bier ◽  
Máté Vass ◽  
Anna J Székely ◽  
Silke Langenheder
Keyword(s):  
Community Assembly ◽  
Temporal Dynamics ◽  
Bacterial Community Composition ◽  
Dispersal Limitation ◽  
Priority Effects ◽  
Environmental Fluctuation ◽  
Species Sorting ◽  
Ecosystem Size ◽  
Environmental Fluctuations ◽  
Over Time

Understanding processes that determine community membership and abundance is important for many fields from theoretical community ecology to conservation. However, spatial community studies are often conducted only at a single timepoint despite the known influence of temporal variability on community assembly processes. Here we used a spatiotemporal study to determine how environmental fluctuation differences induced by mesocosm volumes (larger volumes were more stable) influence assembly processes of aquatic bacterial metacommunities along a press disturbance gradient. By combining path analysis and network approaches, we found mesocosm size categories had distinct relative influences of assembly process and environmental factors that determined spatiotemporal bacterial community composition, including dispersal and species sorting by conductivity. These processes depended on, but were not affected proportionately by, mesocosm size. Low fluctuation, large mesocosms primarily developed through the interplay of species sorting that became more important over time and transient priority effects as evidenced by more time-delayed associations. High fluctuation, small mesocosms had regular disruptions to species sorting and greater importance of ecological drift and dispersal limitation indicated by lower richness and higher taxa replacement. Together, these results emphasize that environmental fluctuations influence ecosystems over time and its impacts are modified by biotic properties intrinsic to ecosystem size.

scholarly journals Environmental filtering and spatial processes equally contributed to macroinvertebrate metacommunity dynamics in the highly urbanized river networks in Shenzhen, South China

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhenyuan Liu ◽  
Tingting Zhou ◽  
Yongde Cui ◽  
Zhengfei Li ◽  
Weimin Wang ◽  
...  
Keyword(s):  
South China ◽  
Community Dynamics ◽  
Environmental Filtering ◽  
Ecological Factors ◽  
Urban River ◽  
River Networks ◽  
Ecological Communities ◽  
Spatial Processes ◽  
Metacommunity Ecology ◽  
Dry Seasons

Abstract Background Disentangling the relative roles of environmental filtering and spatial processes in structuring ecological communities is a central topic in metacommunity ecology. Metacommunity ecology in the temperate river ecosystems has been well developed, while less attention has been paid to subtropical urban river networks. Here, we examined the ecological factors and seasonal difference in structuring macroinvertebrates metacommunity assembly in the subtropical urban river networks in Shenzhen, South China. Results Our results revealed that there was no significant distinction of macroinvertebrate community composition among seasons, with only the relative abundance of Mollusca and Odonata significantly differed in both wet and dry seasons. One possible explanation was that most macroinvertebrates are generally pollution-tolerant taxa characterized with nonseasonal life cycle. In addition, distance-based redundancy analysis and variation partitioning approach revealed that metacommunity was determined equally by the environmental and dispersal-related factors. Further, our results showed that, although a slight temporal variation of relative contribution, the identity and explanation power of ecological factors were different among seasons. Specifically, stronger environmental filtering structuring community dynamics was observed in the dry than wet seasons, which might be owing to higher environmental heterogeneity under a low water-flow condition. Moreover, we detected that the influence of spatial processes was stronger in the wet than dry seasons, indicating an obvious dispersal processes due to high connectivity among sites. Conclusion Overall, our results revealed that environmental and spatial factors equally explained variations of macroinvertebrate metacommunity, implying the necessity of considering dispersal-related processes structuring ecological communities in river bioassessment programs. Moreover, degraded habitat conditions and water quality were the predominant factors that affected macroinvertebrate communities, indicating the significance and feasibility of improving local abiotic conditions to sustain local biodiversity. Further, our findings revealed the importance of seasonal dynamics of these urban river networks in structuring macroinvertebrate metacommunity. Thereby, our study improves the understanding of ecological processes governing macroinvertebrate metacommunity and underlines the idea that community ecology studies should go beyond the single snapshot survey in river networks.

scholarly journals Non-random associations in group housed rats (Rattus norvegicus)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Leanne Proops ◽  
Camille A. Troisi ◽  
Tanja K. Kleinhappel ◽  
Teresa Romero
Keyword(s):  
Network Analysis ◽  
Empirical Evidence ◽  
Rattus Norvegicus ◽  
Dominance Hierarchy ◽  
Group Living ◽  
Ecological Factors ◽  
Limited Evidence ◽  
Rat Strains ◽  
Social Species ◽  
Over Time

AbstractEcological factors, such as predation, have traditionally been used to explain sociability. However, it is increasingly recognised that individuals within a group do not associate randomly, and that these non-random associations can generate fitness advantages. The majority of the empirical evidence on differentiated associations in group-living mammals, however, comes from a limited number of taxa and we still know very little about their occurrence and characteristics in some highly social species, such as rats (Rattus spp.). Here, using network analysis, we quantified association patterns in four groups of male fancy rats. We found that the associations between rats were not randomly distributed and that most individuals had significantly more preferred/avoided associates than expected by random. We also found that these preferences can be stable over time, and that they were not influenced by individuals’ rank position in the dominance hierarchy. Our findings are consistent with work in other mammals, but contrast with the limited evidence available for other rat strains. While further studies in groups with different demographic composition are warranted to confirm our findings, the occurrence of differentiated associations in all male groups of rats have important implications for the management and welfare of captive rat populations.

scholarly journals Acute symptoms of mild to moderate COVID-19 are highly heterogeneous across individuals and over time

2021 ◽  
Author(s):  
Thomas L Rodebaugh ◽  
Madelyn R Frumkin ◽  
Angela M Reiersen ◽  
Eric J Lenze ◽  
Michael S Avidan ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Survey Methods ◽  
Clinical Care ◽  
Clinical Deterioration ◽  
Symptom Profiles ◽  
Fluctuating Course ◽  
The Common ◽  
Symptom Changes ◽  
Over Time

Abstract Background The symptoms of COVID-19 appear to be heterogenous, and the typical course of these symptoms is unknown. Our objectives were to characterize the common trajectories of COVID-19 symptoms and assess how symptom course predicts other symptom changes as well as clinical deterioration. Methods 162 participants with acute COVID-19 responded to surveys up to 31 times for up to 17 days. Several statistical methods were used to characterize the temporal dynamics of these symptoms. Because nine participants showed clinical deterioration, we explored whether these participants showed any differences in symptom profiles. Results Trajectories varied greatly between individuals, with many having persistently severe symptoms or developing new symptoms several days after being diagnosed. A typical trajectory was for a symptom to improve at a decremental rate, with most symptoms still persisting to some degree at the end of the reporting period. The pattern of symptoms over time suggested a fluctuating course for many patients. Participants who showed clinical deterioration were more likely to present with higher reports of severity of cough and diarrhea. Conclusion The course of symptoms during the initial weeks of COVID-19 is highly heterogeneous and is neither predictable nor easily characterized using typical survey methods. This has implications for clinical care and early-treatment clinical trials. Additional research is needed to determine whether the decelerating improvement pattern seen in our data is related to the phenomenon of patients reporting long-term symptoms, and whether higher symptoms of diarrhea in early illness presages deterioration.

scholarly journals Longitudinal Patterns of Ethical Organisational Culture as a Context for Leaders’ Well-Being: Cumulative Effects Over 6 Years

2021 ◽  
Author(s):  
Mari Huhtala ◽  
Muel Kaptein ◽  
Joona Muotka ◽  
Taru Feldt
Keyword(s):  
Latent Profile Analysis ◽  
Temporal Dynamics ◽  
Ethical Dilemmas ◽  
Extended Period ◽  
Well Being ◽  
Organisational Culture ◽  
Cumulative Effects ◽  
Ethical Culture ◽  
Continuous Increase ◽  
Over Time

AbstractThe aim of this longitudinal study was to investigate the temporal dynamics of ethical organisational culture and how it associates with well-being at work when potential changes in ethical culture are measured over an extended period of 6 years. We used a person-centred study design, which allowed us to detect both typical and atypical patterns of ethical culture stability as well as change among a sample of leaders. Based on latent profile analysis and hierarchical linear modelling we found longitudinal, concurrent relations and cumulative gain and loss cycles between different ethical culture patterns and leaders’ well-being. Leaders in the strongest ethical culture pattern experienced the highest level of work engagement and a decreasing level of ethical dilemmas and stress. Leaders who gave the lowest ratings on ethical culture which also decreased over time reported the highest level of ethical dilemmas, stress, and burnout. They also showed a continuous increase in these negative outcomes over time. Thus, ethical culture has significant cumulative effects on well-being, and these longitudinal effects can be both negative and positive, depending on the experienced strength of the culture’s ethicality.

scholarly journals 520. Longitudinal Analysis of SARS-CoV-2 Viruses in Hospitalized Adults

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S325-S326
Author(s):  
Lacy Simons ◽  
Ramon Lorenzo-Redondo ◽  
Hannah Nam ◽  
Scott C Roberts ◽  
Michael G Ison ◽  
...  
Keyword(s):  
Viral Load ◽  
Genome Sequencing ◽  
Viral Genome ◽  
Temporal Dynamics ◽  
Population Level ◽  
Hospital Staff ◽  
Therapeutic Interventions ◽  
Viral Loads ◽  
Qrt Pcr ◽  
Over Time

Abstract Background The rapid spread of SARS-CoV-2, the causative agent of Coronavirus disease 2019 (COVID-19), has been accompanied by the emergence of viral mutations, some of which may have distinct virological and clinical consequences. While whole genome sequencing efforts have worked to map this viral diversity at the population level, little is known about how SARS-CoV-2 may diversify within a host over time. This is particularly important for understanding the emergence of viral resistance to therapeutic interventions and immune pressure. The goal of this study was to assess the change in viral load and viral genome sequence within patients over time and determine if these changes correlate with clinical and/or demographic parameters. Methods Hospitalized patients admitted to Northwestern Memorial Hospital with a positive SARS-CoV-2 test were enrolled in a longitudinal study for the serial collection of nasopharyngeal specimens. Swabs were administered to patients by hospital staff every 4 ± 1 days for up to 32 days or until the patients were discharged. RNA was extracted from each specimen and viral loads were calculated by quantitative reverse transcriptase PCR (qRT-PCR). Specimens with qRT-PCR cycle threshold values less than or equal to 30 were subject to whole viral genome sequencing by reverse transcription, multiplex PCR, and deep sequencing. Variant populations sizes were estimated and subject to phylogenetic analysis relative to publicly available SARS-CoV-2 sequences. Sequence and viral load data were subsequently correlated to available demographic and clinical data. Results 60 patients were enrolled from March 26th to June 20th, 2020. We observed an overall decrease in nasopharyngeal viral load over time across all patients. However, the temporal dynamics of viral load differed on a patient-by-patient basis. Several mutations were also observed to have emerged within patients over time. Distribution of SARS-CoV-2 viral loads in serially collected nasopharyngeal swabs in hospitalized adults as determined by qRT-PCR. Samples were collected every 4 ± 1 days (T#1–8) and viral load is displayed by log(copy number). Conclusion These data indicate that SARS-CoV-2 viral loads in the nasopharynx decrease over time and that the virus can accumulate mutations during replication within individual patients. Future studies will examine if some of these mutations may provide fitness advantages in the presence of therapeutic and/or immune selective pressures. Disclosures Michael G. Ison, MD MS, AlloVir (Consultant)

scholarly journals Environmental filtering and spatial processes in urban riparian forests

2016 ◽  
Vol 27 (5) ◽  
pp. 1023-1035 ◽  
Author(s):  
Marie-Hélène Brice ◽  
Stéphanie Pellerin ◽  
Monique Poulin
Keyword(s):  
Environmental Filtering ◽  
Riparian Forests ◽  
Spatial Processes

scholarly journals Assembly processes of gastropod community change with horizontal and vertical zonation in ancient Lake Ohrid: a metacommunity speciation perspective

2016 ◽  
Vol 13 (10) ◽  
pp. 2901-2911 ◽  
Author(s):  
Torsten Hauffe ◽  
Christian Albrecht ◽  
Thomas Wilke
Keyword(s):  
Community Composition ◽  
Community Assembly ◽  
Environmental Filtering ◽  
Dispersal Limitation ◽  
Species Interaction ◽  
Relative Importance ◽  
Lake Depth ◽  
Ancient Lake ◽  
Lake Ohrid ◽  
Speciation Model

Abstract. The Balkan Lake Ohrid is the oldest and most diverse freshwater lacustrine system in Europe. However, it remains unclear whether species community composition, as well as the diversification of its endemic taxa, is mainly driven by dispersal limitation, environmental filtering, or species interaction. This calls for a holistic perspective involving both evolutionary processes and ecological dynamics, as provided by the unifying framework of the “metacommunity speciation model”.The current study used the species-rich model taxon Gastropoda to assess how extant communities in Lake Ohrid are structured by performing process-based metacommunity analyses. Specifically, the study aimed (1) to identifying the relative importance of the three community assembly processes and (2) to test whether the importance of these individual processes changes gradually with lake depth or discontinuously with eco-zone shifts.Based on automated eco-zone detection and process-specific simulation steps, we demonstrated that dispersal limitation had the strongest influence on gastropod community composition. However, it was not the exclusive assembly process, but acted together with the other two processes – environmental filtering and species interaction. The relative importance of the community assembly processes varied both with lake depth and eco-zones, though the processes were better predicted by the latter.This suggests that environmental characteristics have a pronounced effect on shaping gastropod communities via assembly processes. Moreover, the study corroborated the high importance of dispersal limitation for both maintaining species richness in Lake Ohrid (through its impact on community composition) and generating endemic biodiversity (via its influence on diversification processes). However, according to the metacommunity speciation model, the inferred importance of environmental filtering and biotic interaction also suggests a small but significant influence of ecological speciation. These findings contribute to the main goal of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) deep drilling initiative – inferring the drivers of biotic evolution – and might provide an integrative perspective on biological and limnological dynamics in ancient Lake Ohrid.

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