Biology subjects

Hering, D.

Publications and source records attributed to Hering, D..

5 recordsLinked to original sources

bioRxiv2024

Global-scale quantification of responses to anthropogenic stressors in six riverine organism groups

Rivers globally are impacted by numerous anthropogenic stressors, including water pollution, habitat degradation, and climate change, which collectively stress biodiversity and ecosystem functioning. This study systematically reviews and analyses published and unpublished data to understand how five aquatic organism groups (bacteria, algae, macrophytes, invertebrates, fish) respond to seven common stressors (salinization, oxygen depletion, fine sediment enrichment, temperature increase, flow modifications and nitrogen or phosphorus enrichment). Using an analytical framework that includes Generalized Linear Models (GLMs) and Robust Bayesian Meta Analysis (RoBMA), we extracted data from 143 relevant datasets out of 29,749 screened articles. Our results reveal a negative relationship between invertebrates and salinity, fine sediment enrichment, and temperature increase, while fish respond positively to increased oxygen levels and temperature. Bacteria and algae show variable responses, with algae positively associated with nitrogen. The findings highlight strong variability in stressor-response relations across organism groups and stressor types, and emphasize the need for more targeted studies on underrepresented groups like macrophytes and microorganisms. This analysis enhances the predictive understanding of stressor impacts on riverine biodiversity, informing future river ecosystem management and restoration efforts.

ecology↗

bioRxiv2024

Drivers of recovery and degradation of riverine benthic macroinvertebrate communities: A nationwide analysis of time series

In response to the global freshwater biodiversity crisis this study examines the drivers, influencing recovery and degradation in riverine benthic macroinvertebrate communities across Germany. Utilizing the Asymmetric Response Concept (ARC), which posits that species tolerances to stressors, dispersal capacity, and biotic interactions are critical drivers in aquatic ecosystem recovery, we analyzed a comprehensive dataset from 1568 sites, sampled between 2004 and 2022. Our findings indicate that abiotic stress consistently influences ecological status in both recovery and degradation phases. Interspecific competition shows a stronger positive relationship with ecological status improvements during recovery phases than during degradation, underscoring its importance in the recovery process. Additionally, land use intensity has a nuanced impact: catchments with higher proportions of cropland and urban areas are more likely to recover, while forested catchments are more prone to degradation. This study supports the ARC and highlights the complex interplay of biotic and abiotic variables in shaping ecological outcomes, underscoring the importance of integrated management approaches in freshwater conservation and restoration efforts.

ecology↗

bioRxiv2024

Contributions of source populations, habitat suitability and trait overlap to benthic invertebrate community assembly in restored urban streams

Community development in restored streams is often slow or even absent, but reasons remain obscure. Inadequate restoration measures, catchment-scale pressures, community closure and colonization barriers all may prevent or slow down recovery processes. For initial colonization, dispersal processes are supposed to be most important, which are referred to as dispersal filter. Environmental conditions of a restored reach determine if a dispersing species can successfully establish (environmental filter). Lastly, while available niches at those reaches fill up, biotic interactions, such as competition, become more important (biotic filter). To investigate the importance of these different filters, we compared benthic invertebrate communities of 20 sites in the Boye catchment (Western Germany), a former open sewer system. The sites were grouped, based on the years since restoration, into unimpacted (never restored), recently restored (< 4 years) and mature restored (> 10 years) sites. Data collected at 28 additional sites in the catchment informed us on distances to potential source populations. Habitat suitability describes the fit between environmental conditions (abiotic site data) and species preferences and was used to assess the role of environmental filtering. We evaluated the role of the biotic filter based on trait overlap, referring to possible interspecific competition. Communities collected at recently restored sites differed from those of mature restored and unimpacted sites. Taxa present at recently restored and mature sites had closer source populations than those of unimpacted sites. Taxa at mature and unimpacted sites had a better fit to the present habitats than those of recently restored sites. The trait overlap did not differ between co-occurring and not co-occurring taxa at any of the site groups. Our findings show that communities of mature restored sites that have been restored more than 10 years ago, resembled those of unimpacted sites. Dispersal was most important in early years of recovery. Taxa occurrences at sites with nearby source populations and low habitat suitability are likely the result of high rates of dispersal from upstream sources (mass effects). These can be caused by hatching events or environmental disturbances. Habitat suitability played a larger role for communities at mature and unimpacted sites which indicates that optimal communities shape over time. We did not find indications that competition played a role for community assembly. Hence, dispersal and habitat suitability were most relevant for species occurrences. Competition could be more important on micro scales and the results may differ if species abundances are taken into account. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/601525v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@83da2eorg.highwire.dtl.DTLVardef@693dc4org.highwire.dtl.DTLVardef@1564eaborg.highwire.dtl.DTLVardef@146ee79_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗

bioRxiv2022

Effects of woody riparian vegetation on macroinvertebratesare context-specific and large in urban and especiallyagricultural landscapes

O_LIWoody riparian vegetation (WRV) benefits benthic macroinvertebrates. However, in recent large scale studies, the effects of WRV on macroinvertebrates were small compared to catchment landuse, raising the question about the relevance of WRV in restoration. Limited effects of WRV might be due to context specificity: While some functions are provided by WRV irrespective of catchment landuse, others depend on the landscape setting. C_LIO_LIRecursive partitioning modelling was used to identify context dependent effects of WRV on streams macroinvertebrates ecological status in small lowland (n = 361) and mountain streams (n = 748). WRV cover was quantified from orthophotos along the near (500 m) and far (5,000 m) upstream river network and used to predict the sites ecological status. Agricultural, urban and woodland cover at the local and catchment scales along with hydromorphology were considered as partitioning variables. C_LIO_LIIn rural agricultural landscapes, the effect of WRV on the ecological status was large, indicating that establishing WRV can improve the ecological status by as much as two classes. C_LIO_LIIn streams impacted by catchment urbanization, effects of WRV were largest, but WRV cover and ecological status were both low, indicating practical limitations of WRV restoration in urban catchments. C_LIO_LISynthesis and applications: Independent effects of WRV on macroinvertebrates ecological status can be discerned from catchment landuse. While WRV can also improve the ecological status in urban settings, it is especially relevant for river management in rural agricultural catchments, where developing WRV potentially are effective measures to reach good ecological status C_LI

ecology↗

bioRxiv2021

GPR55 in B cells limits atherosclerosis development and regulates plasma cell maturation

Identifying novel pathways regulating the adaptive immune response in chronic inflammatory diseases such as atherosclerosis is of particular interest in view of developing new therapeutic drugs. Here we report that the lipid receptor GPR55 is highly expressed by splenic B cells and inversely correlates with atheroma plaque size in mice. In human carotid endarterectomy specimen, GPR55 transcript levels were significantly lower in unstable compared to stable carotid plaques. To study the impact of GPR55 deficiency in atherosclerosis, we crossed Gpr55 knockout mice with apolipoprotein E (ApoE) knockout mice and subjected the mice to Western diet for 4 to 16 weeks. Compared to ApoE-/- controls, ApoE-/-Gpr55-/- mice developed larger plaques with increased necrotic core size, associated with elevated circulating and aortic leukocyte counts. Flow cytometry, immunofluorescence and RNA-sequencing analysis of splenic B cells in these mice revealed a hyperactivated B cell phenotype with disturbed plasma cell maturation and immunoglobulin (Ig)G antibody overproduction. The specific contribution of B cell GPR55 in atherosclerosis was further studied in mixed Gpr55-/-/{micro}MT bone marrow chimeras on low density receptor deficiency (Ldlr-/-) background, revealing that B-cell specific depletion of Gpr55 was sufficient to promote plaque development. Conversely, adoptive transfer of wildtype B cells into ApoE-/-Gpr55-/- mice blunted the proatherogenic phenotype. In vitro stimulation of splenocytes with the endogenous GPR55 ligand LPI promoted plasma cell proliferation and enhanced B cell activation marker expression, which was inhibited by the GPR55 antagonist CID16020046. Collectively, these discoveries provide new evidence for GPR55 as key modulator of the adaptive immune response in atherosclerosis. Targeting GPR55 could be useful to limit inflammation and plaque progression in patients suffering from atherosclerosis.

immunology↗