scholarly journals Contrasting effects of anthropogenic and natural acidity in streams: a meta-analysis

2008 ◽  
Vol 275 (1639) ◽  
pp. 1143-1148 ◽  
Author(s):  
Zlatko Petrin ◽  
Göran Englund ◽  
Björn Malmqvist
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Water Chemistry ◽  
Large Scale ◽  
Meta Analysis ◽  
Continental Scale ◽  
Small Streams ◽  
Natural Acidity ◽  
Macroinvertebrate Species ◽  
Ecological Functioning

Large-scale human activities including the extensive combustion of fossil fuels have caused acidification of freshwater systems on a continental scale, resulting in reduced species diversity and, in some instances, impaired ecological functioning. In regions where acidity is natural, however, species diversity and functioning seem to be less affected. This contrasting response is likely to have more than one explanation including the possibility of adaptation in organisms exposed to natural acidity over evolutionary time scales and differential toxicity due to dissimilarities in water chemistry other than pH. However, empirical evidence supporting these hypotheses is equivocal. Partly, this is because previous research has mainly been conducted at relatively small geographical scales, and information on ecological functioning in this context is generally scarce. Our goal was to test whether anthropogenic acidity has stronger negative effects on species diversity and ecological functioning than natural acidity. Using a meta-analytic approach based on 60 datasets, we show that macroinvertebrate species richness and the decomposition of leaf litter—an important process in small streams—tend to decrease with increasing acidity across regions and across both the acidity categories. Macroinvertebrate species richness, however, declines three times more rapidly with increasing acidity where it is anthropogenic than where it is natural, in agreement with the adaptation hypothesis and the hypothesis of differences in water chemistry. By contrast, the loss in ecological functioning differs little between the categories, probably because increases in the biomass of taxa remaining at low pH compensate for losses in functionality that would otherwise accompany losses of taxa from acidic systems. This example from freshwater acidification illustrates how natural and anthropogenic stressors can differ markedly in their effects on species diversity and one aspect of ecological functioning.

scholarly journals Influence of the environmental factors on species diversity and quantitative development of zoobenthos in the Neva Bay

2018 ◽  
Vol 322 (1) ◽  
pp. 50-65
Author(s):  
E.V. Balushkina ◽  
M.S. Golubkov
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Primary Production ◽  
Large Scale ◽  
Structural Characteristics ◽  
Abiotic Factors ◽  
Chlorophyll Concentration ◽  
Benthic Fauna ◽  
Anthropogenic Stress ◽  
Neva Bay

Hydrochemical characteristics, primary production of plankton, taxonomic composition, species richness, species diversity and quantitative characteristics of the benthic fauna of the Neva Bay had been collected and analyzed at the end of July and the very beginning of August 2003–2012 by the method stepwise regression, calculated equations with a free constant. Effects of biotic and abiotic factors on the structural and functional characteristics of benthic communities in the Neva Bay were evaluated using multiregression analysis. Research period had been accompanied by revival of industry of Saint-Petersburg, construction of ports, active navigation, development of Sea facade and completion of the construction of the St. Petersburg Flood Prevention Facility Complex and a large-scale hydrotechnical works: building of a Marine Multifunctional Reloading Complex (MMRC) “Bronka” and approach fairway to it. Results of statistical analysis showed that the number of species and species diversity of bottom animals in the Neva Bay declined with increased primary production and chlorophyll a concentration. Analysis of the factors influencing the values of biomass of benthic animal communities shows that these characteristics increased with growing chlorophyll concentration. During the anthropogenic stress of 2006–2007, the existing links between the structural characteristics of the zoobenthos and the functional biotic characteristics of the Neva Bay were completely destroyed. Restoration period 2008–2012 was accompanied by an increase in the species richness and species diversity of zoobenthos to the level observed before anthropogenic stress.

scholarly journals Trophic interactions among vertebrate guilds and plants shape global patterns in species diversity

2018 ◽  
Vol 285 (1883) ◽  
pp. 20180949 ◽  
Author(s):  
Jian Zhang ◽  
Hong Qian ◽  
Marco Girardello ◽  
Vincent Pellissier ◽  
Scott E. Nielsen ◽  
...  
Keyword(s):  
Species Richness ◽  
Species Diversity ◽  
Trophic Interactions ◽  
Large Scale ◽  
Environmental Drivers ◽  
Top Down ◽  
Bottom Up ◽  
Diversity Patterns ◽  
Biodiversity Patterns ◽  
Global Patterns

Trophic interactions play critical roles in structuring biotic communities. Understanding variation in trophic interactions among systems provides important insights into biodiversity maintenance and conservation. However, the relative importance of bottom-up versus top-down trophic processes for broad-scale patterns in biodiversity is poorly understood. Here, we used global datasets on species richness of vascular plants, mammals and breeding birds to evaluate the role of trophic interactions in shaping large-scale diversity patterns. Specifically, we used non-recursive structural equation models to test for top-down and bottom-up forcing of global species diversity patterns among plants and trophic guilds of mammals and birds (carnivores, invertivores and herbivores), while accounting for extrinsic environmental drivers. The results show that trophic linkages emerged as being more important to explaining species richness than extrinsic environmental drivers. In particular, there were strong, positive top-down interactions between mammal herbivores and plants, and moderate to strong bottom-up and/or top-down interactions between herbivores/invertivores and carnivores. Estimated trophic interactions for separate biogeographical regions were consistent with global patterns. Our findings demonstrate that, after accounting for environmental drivers, large-scale species richness patterns in plant and vertebrate taxa consistently support trophic interactions playing a major role in shaping global patterns in biodiversity. Furthermore, these results suggest that top-down forces often play strong complementary roles relative to bottom-up drivers in structuring biodiversity patterns across trophic levels. These findings underscore the importance of integrating trophic forcing mechanisms into studies of biodiversity patterns.

Relationship between total plasma homocysteine and the risk of aneurysms – a meta-analysis

VASA ◽  
2020 ◽  
pp. 1-6
Author(s):  
Hanji Zhang ◽  
Dexin Yin ◽  
Yue Zhao ◽  
Yezhou Li ◽  
Dejiang Yao ◽  
...  
Keyword(s):  
Large Scale ◽  
Meta Analysis ◽  
Single Species ◽  
Total Plasma ◽  
Control Groups ◽  
Randomized Controlled ◽  
Randomized Controlled Studies ◽  
The Difference ◽  
The Relationship ◽  
Healthy Participants

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

Identification of and Correction for Publication Bias: Comment

2019 ◽  
Author(s):  
Amanda Kvarven ◽  
Eirik Strømland ◽  
Magnus Johannesson
Keyword(s):  
Publication Bias ◽  
False Positive ◽  
Large Scale ◽  
Meta Analysis ◽  
False Positive Rate ◽  
Effect Sizes ◽  
Replication Studies ◽  
Moderate Reduction ◽  
Positive Rate ◽  
Meta Analyses

Andrews & Kasy (2019) propose an approach for adjusting effect sizes in meta-analysis for publication bias. We use the Andrews-Kasy estimator to adjust the result of 15 meta-analyses and compare the adjusted results to 15 large-scale multiple labs replication studies estimating the same effects. The pre-registered replications provide precisely estimated effect sizes, which do not suffer from publication bias. The Andrews-Kasy approach leads to a moderate reduction of the inflated effect sizes in the meta-analyses. However, the approach still overestimates effect sizes by a factor of about two or more and has an estimated false positive rate of between 57% and 100%.

Association between ALDH2 Gene Polymorphism and Late-onset Alzheimer Disease: An Up-to-date Meta-analysis

2020 ◽  
Vol 17 (2) ◽  
pp. 105-111
Author(s):  
Haitao Liu ◽  
Wei Ge ◽  
Wei Chen ◽  
Xue Kong ◽  
Weiming Jian ◽  
...  
Keyword(s):  
Gene Polymorphism ◽  
Large Scale ◽  
Late Onset ◽  
Meta Analysis ◽  
Case Control ◽  
Cochrane Library ◽  
Positive Trend ◽  
Case Control Studies ◽  
China National Knowledge Infrastructure ◽  
Aldh2 Gene

Objectives: Previous case-control studies have focused on the relationship between ALDH2 gene polymorphism and late-onset Alzheimer's Disease (LOAD), but no definite unified conclusion has been reached. Therefore, the correlation between ALDH2 Glu504Lys polymorphism and LOAD remains controversial. To analyze the correlation between ALDH2 polymorphism and the risk of LOAD, we implemented this up-to-date meta-analysis to assess the probable association. Methods: Studies were searched through China National Knowledge Infrastructure (CNKI), VIP Database for Chinese Technical Periodicals, China Biology Medicine, PubMed, Cochrane Library, Clinical- Trials.gov, Embase, and MEDLINE from January 1, 1994 to December 31, 2018, without any restrictions on language and ethnicity. Results: Five studies of 1057 LOAD patients and 1136 healthy controls met our criteria for the analysis. Statistically, the ALDH2 GA/AA genotype was not linked with raising LOAD risk (odds ratio (OR) = 1.48, 95% confidence interval (CI) = 0.96-2.28, p = 0.07). In subgroup analysis, the phenomenon that men with ALDH2*2 had higher risk for LOAD (OR = 1.72, 95%CI = 1.10-2.67, p = 0.02) was observed. Conclusions: This study comprehends only five existing case-control studies and the result is negative. The positive trend might appear when the sample size is enlarged. In the future, more large-scale casecontrol or cohort studies should be done to enhance the association between ALDH2 polymorphism and AD or other neurodegenerative diseases.

Serum Copper Level and Polycystic Ovarian Syndrome: A Meta-Analysis

2021 ◽  
pp. 1-8
Author(s):  
Qingtao Jiang ◽  
Feng Zhang ◽  
Lei Han ◽  
Baoli Zhu ◽  
Xin Liu
Keyword(s):  
Large Scale ◽  
Polycystic Ovarian Syndrome ◽  
Meta Analysis ◽  
Serum Copper ◽  
Copper Level ◽  
Serum Copper Level ◽  
Copper Status ◽  
Plasma Copper ◽  
Mean Differences ◽  
Ovarian Syndrome

<b><i>Introduction:</i></b> The association of serum copper with polycystic ovarian syndrome (PCOS) has been studied for years, but no definite conclusion is drawn. Therefore, we conducted a meta-analysis to investigate serum copper concentrations in PCOS subjects compared with healthy controls. <b><i>Methods:</i></b> Electronic search was performed in PubMed, Google Scholar, and Scopus up to June 30, 2020, without any restriction. Standardized mean differences (SMDs) with corresponding 95% CIs in serum copper levels were employed with random-effects model. <i>I</i><sup>2</sup> was applied to evaluate heterogeneity among studies. <b><i>Results:</i></b> Nine studies, measuring plasma copper levels in 1,168 PCOS patients and 1,106 controls, were included. Pooled effect size suggested serum copper level was significantly higher in women with PCOS (SMD = 0.51 μg/mL, 95% CI = [0.30, 0.72], <i>p</i> &#x3c; 0.0001). The overall heterogeneity was not connected with subgroups of the country, but derived from the opposite result of 1 study. <b><i>Conclusion:</i></b> Our research generally indicated circulating copper level in PCOS sufferers was significantly higher than normal controls. Large-scale studies are still needed to elucidate the clear relation between copper status and etiology of PCOS.

scholarly journals Family graveyards form underappreciated local plant diversity hotspots in China's agricultural landscapes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cheng Gong ◽  
Liangtao Li ◽  
Jan C. Axmarcher ◽  
Zhenrong Yu ◽  
Yunhui Liu
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Natural Habitat ◽  
Plant Species Richness ◽  
Agricultural Landscapes ◽  
Natural Habitats ◽  
Landscape Features ◽  
Habitat Islands ◽  
Local Plant ◽  
Ecological Functioning

AbstractIn the intensively farmed, homogenous agricultural landscape of the North China Plain, family graveyards form distinct cultural landscape features. In addition to their cultural value, these graveyards represent semi-natural habitat islands whose potential roles in biodiversity conservation and ecological functioning has remained poorly understood. In this study, we investigated plant species richness on 199 family graveyards of different ages and sizes. In accordance with biogeography theory, both overall and insect-pollinated plant species richness increased with area and age of graveyards. Even small graveyards show a strong potential for conserving local plant richness, and a mosaic of both large and small family graveyards could play an important role in the conservation of farmland biodiversity and related ecosystem functions. The launch of agri-environmental measures that conserve and create semi-natural habitats, in turn benefitting agricultural biodiversity and ecological functioning, has proven difficult in China due to the shortage of dispensable arable land. Given the great value of family graveyards as semi-natural habitats reflected in our study, we propose to focus preliminary efforts on conserving these landscape features as existing, widespread and culturally important semi-natural habitat islands. This would represent an effective, complementary policy to a subsequent re-establishment of other semi-natural habitats for the conservation of biodiversity and ecological functioning in agricultural landscapes.

scholarly journals Efficacy and safety of Si-Jun-Zi-Tang-based therapies for functional (non-ulcer) dyspepsia: a meta-analysis of randomized controlled trials

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yaping Wang ◽  
Bin Liu ◽  
Xiuqiong Fu ◽  
Tiejun Tong ◽  
Zhiling Yu
Keyword(s):  
Relapse Rate ◽  
Large Scale ◽  
Primary Outcome ◽  
Response Rate ◽  
Meta Analysis ◽  
Risk Of Bias ◽  
Efficacy And Safety ◽  
History Of ◽  
Non Ulcer Dyspepsia

Abstract Background The traditional Chinese medicine formula Si-Jun-Zi-Tang (SJZT) has a long history of application in the treatment of functional dyspepsia (non-ulcer dyspepsia, FD)-like symptoms. SJZT-based therapies have been claimed to be beneficial in managing FD. This study aimed to assess the efficacy and safety of SJZT-based therapies in treating FD by meta-analysis. Methods Systematic searches for RCTs were conducted in seven databases (up to February 2019) without language restrictions. Data were analyzed using Cochrane RevMan software version 5.3.0 and Stata software version 13.1, and reported as relative risk (RR) or odds ratio (OR) with 95% confidence intervals (CIs). The primary outcome was response rate and the secondary outcomes were gastric emptying, quality of life, adverse effects and relapse rate. The quality of evidence was evaluated according to criteria from the Cochrane risk of bias. Results A total of 341 potentially relevant publications were identified, and 12 RCTs were eligible for inclusion. For the response rate, there was a statically significant benefit in favor of SJZT-based therapies (RR = 1.23; 95% CI 1.17 to 1.30). However, the benefit was limited to modified SJZT (MSJZT). The relapse rate of FD patients received SJZT-based therapies was lower than that of patients who received conventional medicines (OR = 0.23; 95% CI 0.10 to 0.51). No SJZT-based therapies-related adverse effect was reported. Conclusion SJZT-based prescriptions may be effective in treating FD and no serious side-effects were identified, but the effect on response rate appeared to be limited to MSJZT. The results should be interpreted with caution as all the included studies were considered at a high risk of bias. Standardized, large-scale and strictly designed RCTs are needed to further validate the benefits of SJZT-based therapies for FD management. Trial registration Systematic review registration: [PROSPERO registration: CRD42019139136].

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