Scientific synthesis is a rapidly evolving field of meta-science pivotal to numerous dimensions of the scientific endeavor and to society at large. In science, meta-analyses, systematic reviews, and evidence mapping are powerful explanatory means to aggregate evidence. However, direct compilation of existing primary evidence is also increasingly common to explore the big picture for pattern and process detection and is used to augment more common synthesis tools. Meta-analyses of primary study literature can be combined with open data assets reporting frequency, distribution, and traits of species. Climate, land-use, and other measures of ecosystem-level attributes can also be derived to support literature syntheses. In society, evidence-based decision making is best served through a diversity of synthesis outcomes in addition to meta-analyses and reviews. The hypothesis tested in this meta-science synthesis is that the diversity of tools and evidence to scientific syntheses has changed in contemporary ecology and environmental sciences to more comprehensively reuse and incorporate evidence for knowledge production.
Case studies and a formal examination of the scope and extent of the literature reporting scientific synthesis as the primary focus in the environmental sciences and ecology were done. Topically, nearly 700 studies use scientific synthesis in some capacity in these two fields. Specifically, less than a dozen formally incorporate disparate evidence to connect related concepts. Meta-analyses and formal systematic reviews number at over 5000 publications. Syntheses and aggregations of existing published aggregations are relatively uncommon at less than 10 instances. Reviews, discussions, forums, and notes examining synthesis in these two fields are also frequent at 2500 offerings. Analyses of contemporary subsets of all these publications in the literature identified at least three common themes. Reuse and reproducibility, effect sizes and strength of evidence, and a comprehensive need for linkages to inform decision making. Specific novel tools used to explore derived data for evidence-based decision making in the environmental sciences and ecology included evidence maps, summaries of lessons, identification of flagship studies in the environmental studies that transformed decision making, reporting of sample sizes at many levels that supported effect size calculations, and finally, reporting of a path forward not just for additional research but for application. Collectively, this meta-synthesis of research demonstrated an increasing capacity for diverse scientific syntheses to inform decision making for the environmental sciences.