Growth performance, windthrow, and insects: meta-analyses of parameters influencing performance of mixed-species stands in boreal and northern temperate biomes

2011 ◽  
Vol 41 (6) ◽  
pp. 1141-1159 ◽  
Author(s):  
Verena C. Griess ◽  
Thomas Knoke
Keyword(s):  
Growth Performance ◽  
Tree Species ◽  
Stand Structure ◽  
Positive Impact ◽  
Meta Analysis ◽  
Positive Interactions ◽  
Negative Effects ◽  
Mixed Species ◽  
Financial Return ◽  
Meta Analyses

Stand structure is a key attribute of forest ecosystems. Mixed-tree plantations are widely felt to be the appropriate option for providing a broad range of goods and environmental services and to reduce susceptibility to natural hazards. However, the debate continues whether mixed plantations can achieve greater financial return than monocultures can. In this study, mixed-species stands of conifers and hardwood species were analyzed in consideration of economically relevant factors. Growth performance and resistance to hazards and pests are widely noted in the literature and are of general economic interest. Thus meta-analyses of relevant studies were conducted to test the following hypotheses: (1) mixing tree species has no significant influence on growth performance or resistance against hazards and pests and, if refuted, (2) mixing tree species causes mainly negative effects on growth performance and resistance against hazards and pests. However, a positive impact of mixing tree species was proven for resistance against windthrow and pests. The meta-analysis on growth performance just as well indicates a positive effect of mixing tree species. Overall, these positive results underscore the need for a large number of additional studies to examine different silvicultural systems to develop optimal management prescriptions to benefit from positive interactions.

scholarly journals The potential of mixing timber assets to financially offset negative effects of deer browsing on western redcedar

2015 ◽  
Vol 91 (04) ◽  
pp. 436-443 ◽  
Author(s):  
Verena C. Griess ◽  
Rajat Panwar ◽  
Julie Cool
Keyword(s):  
Western Hemlock ◽  
Investment Risk ◽  
Financial Indicators ◽  
Negative Effects ◽  
Mixed Species ◽  
Financial Return ◽  
Protective Measures ◽  
Western Redcedar ◽  
Risk Return ◽  
Mixed Species Forest

Western redcedar (WRC) is a highly desirable species in British Columbia's Coastal Western Hemlock zone, both from a management and a conservation perspective. However, it is also highly palatable for ungulates. Existing countermeasures against browsing all have high costs and imperfect results in common. We used the portfolio method to display how diversification can help to lower investment risk. Using risk-return ratios of a WRC and Douglas-fir (DF), we derived species portfolios that yield maximum financial return per unit of risk. Financial indicators were calculated based on Monte Carlo simulations, which consider timber price fluctuation and browsing risk. Results show how economic risks of a forest investment could be reduced by creating a species portfolio. The optimum portfolio leading to most beneficial risk-return combination is 75% WRC and 25% DF if browsing is lowered using protective measures that double planting costs; and 30% WRC and 70% DF if no protective measures are applied. Accordingly, the most desirable risk-return combination is that of a mixed-species forest, whereas the 2 species don't have to be grown in intimate mixtures. Our research sketches a path forward that can help to ensure WRC will remain an important asset in BC's timber portfolio.

scholarly journals Positive biodiversity–productivity relationships in forests: climate matters

2018 ◽  
Vol 14 (4) ◽  
pp. 20170747 ◽  
Author(s):  
H. Jactel ◽  
E. S. Gritti ◽  
L. Drössler ◽  
D. I. Forrester ◽  
W. L. Mason ◽  
...  
Keyword(s):  
Climate Change ◽  
Carbon Sequestration ◽  
Tree Species ◽  
Climatic Factors ◽  
Meta Analysis ◽  
Global Scale ◽  
Tree Age ◽  
Drought Severity ◽  
Natural Forests ◽  
Mixed Species

While it is widely acknowledged that forest biodiversity contributes to climate change mitigation through improved carbon sequestration, conversely how climate affects tree species diversity–forest productivity relationships is still poorly understood. We combined the results of long-term experiments where forest mixtures and corresponding monocultures were compared on the same site to estimate the yield of mixed-species stands at a global scale, and its response to climatic factors. We found positive mixture effects on productivity using a meta-analysis of 126 case studies established at 60 sites spread across five continents. Overall, the productivity of mixed-species forests was 15% greater than the average of their component monocultures, and not statistically lower than the productivity of the best component monoculture. Productivity gains in mixed-species stands were not affected by tree age or stand species composition but significantly increased with local precipitation. The results should guide better use of tree species combinations in managed forests and suggest that increased drought severity under climate change might reduce the atmospheric carbon sequestration capacity of natural forests.

Psychosocial Interventions for Family Carers of People With Dementia: A Systematic Review and Meta-Analysis

2020 ◽  
Vol 32 (9) ◽  
pp. 1198-1213 ◽  
Author(s):  
Áine Teahan ◽  
Attracta Lafferty ◽  
Eilish McAuliffe ◽  
Amanda Phelan ◽  
Liam O’Sullivan ◽  
...  
Keyword(s):  
Social Sciences ◽  
Systematic Review ◽  
Positive Impact ◽  
Meta Analysis ◽  
Psychosocial Interventions ◽  
Future Research ◽  
Family Carers ◽  
People With Dementia ◽  
Meta Analyses ◽  
Study Designs

Objective:This study aimed to review and synthesize findings of the effectiveness of psychosocial interventions aimed at improving outcomes for family carers of people with dementia. Method: A systematic review and meta-analysis were conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We systematically searched the following databases: Cochrane, PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycInfo, Excerpta Medica Database (EMBASE), and Applied Social Sciences Index and Abstracts (ASSIA). RevMan 5 software was used to conduct meta-analysis and subgroup analysis using a random-effects model. Results: The search yielded 22 high-quality intervention articles that were suitable for further meta-analysis. Meta-analysis revealed that psychosocial interventions have a small to moderate significant effect on carer burden (standardized mean difference [SMD] = −0.34, confidence interval [CI] = [−0.59, −0.09]), depression (SMD = −0.36, CI = [−0.60, −0.13]), and general health (SMD = 0.34, CI = [0.18, 0.51]). Discussion: Psychosocial interventions had a positive impact on carer outcomes; however, these results should be interpreted with caution, given the significant level of heterogeneity in study designs. Future research could examine contextual and implementation mechanisms underlying psychosocial interventions to develop effective support systems for family carers of people with dementia.

scholarly journals Does Internet-based guided-self-help for depression cause harm? An individual participant data meta-analysis on deterioration rates and its moderators in randomized controlled trials

2016 ◽  
Vol 46 (13) ◽  
pp. 2679-2693 ◽  
Author(s):  
D. D. Ebert ◽  
L. Donkin ◽  
G. Andersson ◽  
G. Andrews ◽  
T. Berger ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Reliable Change Index ◽  
Cochrane Library ◽  
Pool Data ◽  
Negative Effects ◽  
Self Help ◽  
Increased Risk ◽  
Low Education ◽  
Individual Participant ◽  
Meta Analyses

BackgroundAlmost nothing is known about the potential negative effects of Internet-based psychological treatments for depression. This study aims at investigating deterioration and its moderators within randomized trials on Internet-based guided self-help for adult depression, using an individual patient data meta-analyses (IPDMA) approach.MethodStudies were identified through systematic searches (PubMed, PsycINFO, EMBASE, Cochrane Library). Deterioration in participants was defined as a significant symptom increase according to the reliable change index (i.e. 7.68 points in the CES-D; 7.63 points in the BDI). Two-step IPDMA procedures, with a random-effects model were used to pool data.ResultsA total of 18 studies (21 comparisons, 2079 participants) contributed data to the analysis. The risk for a reliable deterioration from baseline to post-treatment was significantly lower in the intervention v. control conditions (3.36 v. 7.60; relative risk 0.47, 95% confidence interval 0.29–0.75). Education moderated effects on deterioration, with patients with low education displaying a higher risk for deterioration than patients with higher education. Deterioration rates for patients with low education did not differ statistically significantly between intervention and control groups. The benefit–risk ratio for patients with low education indicated that 9.38 patients achieve a treatment response for each patient experiencing a symptom deterioration.ConclusionsInternet-based guided self-help is associated with a mean reduced risk for a symptom deterioration compared to controls. Treatment and symptom progress of patients with low education should be closely monitored, as some patients might face an increased risk for symptom deterioration. Future studies should examine predictors of deterioration in patients with low education.

scholarly journals Goal orientation and performance adaptation: A meta-analysis

2019 ◽  
Author(s):  
Lukasz Stasielowicz
Keyword(s):  
Goal Orientation ◽  
Meta Analysis ◽  
Subjective Ratings ◽  
Negative Effects ◽  
Performance Goal ◽  
Learning Goal Orientation ◽  
And Performance ◽  
Meta Analyses ◽  
Performance Adaptation ◽  
Performance Goal Orientation

The relationship between goal orientation and performance adaptation across studies was assessed in the present article. The relevance of performance adaptation can be exemplified by the desire to optimize performance and mitigate the negative effects of change in organizational and educational contexts (i.e. new co-workers, new software, emergencies). Three-level meta-analyses were conducted for learning goal orientation (LGO) and performance goal orientation (PGO). Furthermore, within PGO a distinction between avoid performance goal orientation (APGO) and prove performance goal orientation (PPGO) could be made. In moderator analyses the influence of measurement method of performance adaptation (subjective ratings vs objective scores) was assessed amongst others. Although significant effects were found they were primarily visible for subjective ratings and not objective scores.

scholarly journals A Meta-Analysis: Improvement of Students’ Algebraic Reasoning through Metacognitive Training

2018 ◽  
Vol 11 (10) ◽  
pp. 42 ◽  
Author(s):  
Yujin Lee ◽  
Mary M. Capraro ◽  
Robert M. Capraro ◽  
Ali Bicer
Keyword(s):  
Effect Size ◽  
Positive Impact ◽  
Meta Analysis ◽  
Effect Sizes ◽  
Algebraic Reasoning ◽  
Metacognitive Training ◽  
Mathematical Performance ◽  
Meta Analyses ◽  
The Impact

Although algebraic reasoning has been considered as an important factor influencing students’ mathematical performance, many students struggle to build concrete algebraic reasoning. Metacognitive training has been regarded as one effective method to develop students’ algebraic reasoning; however, there are no published meta-analyses that include an examination of the effects of metacognitive training on students’ algebraic reasoning. Therefore, the purpose of this meta-analysis was to examine the impact of metacognitive training on students’ algebraic reasoning. Eighteen studies with 22 effect sizes were selected for inclusion in the present meta-analysis. In the process of the analysis, one study was determined as an outlier; therefore, another meta-analysis was reconstructed without the outlier to calculate more robust results. The findings indicated that the overall effect size without an outlier equaled d=0.973 with SE=0.196. Q=20.201 (p<.05) and I2=0.997, which indicated heterogeneity of the studies. These results showed that the metacognitive training had a statistically significant positive impact on students’ algebraic reasoning.

scholarly journals Effects of Beta-Alanine Supplementation on Physical Performance in Aerobic–Anaerobic Transition Zones: A Systematic Review and Meta-Analysis

Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2490
Author(s):  
Álvaro Huerta Ojeda ◽  
Camila Tapia Cerda ◽  
María Fernanda Poblete Salvatierra ◽  
Guillermo Barahona-Fuentes ◽  
Carlos Jorquera Aguilera
Keyword(s):  
Systematic Review ◽  
Physical Performance ◽  
Positive Impact ◽  
Meta Analysis ◽  
Time Trial ◽  
Cochrane Collaboration ◽  
Time To Exhaustion ◽  
Transition Zones ◽  
Beta Alanine ◽  
Meta Analyses

Beta-alanine supplementation (BA) has a positive impact on physical performance. However, evidence showing a benefit of this amino acid in aerobic–anaerobic transition zones is scarce and the results controversial. The aim of this systematic review and meta-analysis is to analyze the effects of BA supplementation on physical performance in aerobic–anaerobic transition zones. At the same time, the effect of different dosages and durations of BA supplementation were identified. The search was designed in accordance with the PRISMA® guidelines for systematic reviews and meta-analyses and performed in Web of Science (WOS), Scopus, SPORTDiscus, PubMed, and MEDLINE between 2010 and 2020. The methodological quality and risk of bias were evaluated with the Cochrane Collaboration tool. The main variables were the Time Trial Test (TTT) and Time to Exhaustion (TTE) tests, the latter separated into the Limited Time Test (LTT) and Limited Distance Test (LDT). The analysis was carried out with a pooled standardized mean difference (SMD) through Hedges’ g test (95% CI). Nineteen studies were included in the systematic review and meta-analysis, revealing a small effect for time in the TTT (SMD, −0.36; 95% CI, −0.87–0.16; I2 = 59%; p = 0.010), a small effect for LTT (SMD, 0.25; 95% CI, −0.01–0.51; I2 = 0%; p = 0.53), and a large effect for LDT (SMD, 4.27; 95% CI, −0.25–8.79; I2 = 94%; p = 0.00001). BA supplementation showed small effects on physical performance in aerobic–anaerobic transition zones. Evidence on acute supplementation is scarce (one study); therefore, exploration of acute supplementation with different dosages and formats on physical performance in aerobic–anaerobic transition zones is needed.

scholarly journals Occupational Therapy in Fatigue Management in Multiple Sclerosis: An Umbrella Review

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Angela Salomè ◽  
Tullia Sasso D’Elia ◽  
Giorgia Franchini ◽  
Valter Santilli ◽  
Teresa Paolucci
Keyword(s):  
Multiple Sclerosis ◽  
Occupational Therapy ◽  
Systematic Reviews ◽  
Work Performance ◽  
Positive Impact ◽  
Meta Analysis ◽  
Cochrane Library ◽  
Umbrella Review ◽  
Fatigue Management ◽  
Meta Analyses

Background. Fatigue is one of the most invalidant symptoms of Multiple Sclerosis (MS) that negatively affects occupational and work performance and social participation. Occupational therapy (OT) assessment and treatment of impairments related to fatigue can have a significant and positive impact on the quality of life. Methods. An umbrella review has been carried out to provide rehabilitative decision makers in healthcare with insight into the role of OT in fatigue management in Multiple Sclerosis. The question is, what type of treatment provided by occupational therapist is more effective in reducing fatigue in Multiple Sclerosis? A search of literature published until June 2018 was undertaken by three independent reviewers using PubMed, PEDro, and Cochrane Library database including systematic reviews and meta-analyses of the last 10 years. Results. 10 studies were selected (5 systematic reviews, 1 meta-analysis, 3 reviews, and 1 guideline). Conclusions. Fatigue management programs have moderate evidence; other strategies such as OT strategies and telerehabilitation show low evidence.

A Meta-Analysis of Interviews and Cognitive Ability

2013 ◽  
Vol 12 (4) ◽  
pp. 157-169 ◽  
Author(s):  
Philip L. Roth ◽  
Allen I. Huffcutt
Keyword(s):  
Cognitive Ability ◽  
Meta Analysis ◽  
Incremental Validity ◽  
Employment Interviews ◽  
Moderator Analysis ◽  
The Future ◽  
Research Questions ◽  
Meta Analyses ◽  
The Relationship

The topic of what interviews measure has received a great deal of attention over the years. One line of research has investigated the relationship between interviews and the construct of cognitive ability. A previous meta-analysis reported an overall corrected correlation of .40 ( Huffcutt, Roth, & McDaniel, 1996 ). A more recent meta-analysis reported a noticeably lower corrected correlation of .27 ( Berry, Sackett, & Landers, 2007 ). After reviewing both meta-analyses, it appears that the two studies posed different research questions. Further, there were a number of coding judgments in Berry et al. that merit review, and there was no moderator analysis for educational versus employment interviews. As a result, we reanalyzed the work by Berry et al. and found a corrected correlation of .42 for employment interviews (.15 higher than Berry et al., a 56% increase). Further, educational interviews were associated with a corrected correlation of .21, supporting their influence as a moderator. We suggest a better estimate of the correlation between employment interviews and cognitive ability is .42, and this takes us “back to the future” in that the better overall estimate of the employment interviews – cognitive ability relationship is roughly .40. This difference has implications for what is being measured by interviews and their incremental validity.

Power-Enhanced Funnel Plots for Meta-Analysis

2020 ◽  
Vol 228 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Michael Kossmeier ◽  
Ulrich S. Tran ◽  
Martin Voracek
Keyword(s):  
Statistical Power ◽  
Meta Analysis ◽  
Relevant Information ◽  
Selective Reporting ◽  
Graphical Display ◽  
Funnel Plot ◽  
Evidential Value ◽  
Graphical Displays ◽  
Funnel Plots ◽  
Meta Analyses

Abstract. Currently, dedicated graphical displays to depict study-level statistical power in the context of meta-analysis are unavailable. Here, we introduce the sunset (power-enhanced) funnel plot to visualize this relevant information for assessing the credibility, or evidential value, of a set of studies. The sunset funnel plot highlights the statistical power of primary studies to detect an underlying true effect of interest in the well-known funnel display with color-coded power regions and a second power axis. This graphical display allows meta-analysts to incorporate power considerations into classic funnel plot assessments of small-study effects. Nominally significant, but low-powered, studies might be seen as less credible and as more likely being affected by selective reporting. We exemplify the application of the sunset funnel plot with two published meta-analyses from medicine and psychology. Software to create this variation of the funnel plot is provided via a tailored R function. In conclusion, the sunset (power-enhanced) funnel plot is a novel and useful graphical display to critically examine and to present study-level power in the context of meta-analysis.

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