Advancing plant ecology through meta‐analyses

Abstract

Summary1. The inherent complexity of nature produces a diverse and varied set of outcomes for any given ecological process. However, the advance of ecology requires making generalizations that synthesize current knowledge and guide new basic research and practical applications. Among the synthesis tools available for this specific purpose, meta-analysis is one of the most accurate and powerful methods. 2. This Special Feature examines the use that meta-analysis has received in plant ecology over the last two decades and provides examples of synthesis applied to contemporary topics in different areas of plant ecology from populations to ecosystems. 3. The number of meta-analyses in plant ecology has been increasing rapidly in the last two decades. However, this increase has not been accompanied by a parallel increase in quality. The opening review paper in this Special Feature provides a checklist of quality criteria specific to ecological meta-analysis that will largely contribute to improvement of the methodological and reporting standards of meta-analyses. 4. The following five papers in the Special Feature demonstrate the advantages of application of meta-analysis compared with other techniques of research synthesis. Meta-analysis is applied here to demonstrate the consistency of ecological hypotheses across large spatial scales (e.g. Janzen-Connell hypothesis), understand sources of variation in the magnitude of ecological processes (e.g. herbivory effects on leaf life span, effects of intraspecific genetic diversity on communities and ecosystems), measure synergistic impacts of environmental change drivers (e.g. CO 2 , drought, land use) or assess research gaps within a certain sub-discipline of plant ecology (e.g. landscape fragmentation). 5. Synthesis. Meta-analysis can contribute to the advance of ecological theory by synthesizing the available evidence on specific topics and informing the scope of generalizations. However, plant ecologists can only take full advantage of this capacity if we improve our knowledge on how and when to conduct a proper meta-analysis, and by avoiding the frequent misuses that have characterized the use of this statistical tool in the ecological literature thus far.

Understory Vegetation Change Following Woodland Reduction Varies by Plant Community Type and Seeding Status: A Region-Wide Assessment of Ecological Benefits and Risks

“…However, the conservation benefits of such treatments have not been consistently realized [ 1 , 77 , 78 , 79 , 80 ], the efficacy of this management strategy has been highly variable, and the longevity of removal/reduction treatments often do not exceed 10 years [ 2 , 78 ]. Consequently, there is critical need for empirical assessments of large-scale restoration projects at the regional scale to uncover patterns in posttreatment vegetation dynamics, enhance our ability to choose the most appropriate site-specific treatments for future restoration [ 80 , 81 , 82 , 83 ], and inform the public on how restoration activities are achieving management goals [ 84 , 85 , 86 , 87 , 88 ].…”

Heterogeneity in ecological and evolutionary meta‐analyses: its magnitude and implications

“…introDuCtion Meta-analysis is the accepted standard for quantitatively synthesizing findings in most fields of research. In ecological and evolutionary research in particular, metaanalysis has become increasingly popular over the last two decades (Nakagawa and Poulin 2012, Vetter et al 2013, Gomez-Aparicio and Lortie 2014, Stewart and Schmid 2015. This approach has been applied to topics ranging from the highly ecological, such as drivers of species invasions, to questions in genetics, such as the strength of heterozygosity-fitness correlations (Chapman et al 2009, Davidson et al 2011.…”

Zen and the art of ecological synthesis

“…Summary publications on best practices and approaches to meta‐analyses and systematic reviews continue to proliferate for ecologists (Vetter et al , Gómez‐Aparicio and Lortie , Koricheva and Gurevitch , Doerr et al , Lortie et al , Shrier ) in addition to the recent handbook (Koricheva et al ). The checklist provided by Koricheva and Gurevitch (Table 2, 2014) for plant ecologists absolutely applies to Oikos submissions.…”