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. Author manuscript; available in PMC: 2020 May 15.
Published in final edited form as: Science. 2019 Nov 15;366(6467):886–890. doi: 10.1126/science.aay2832

Fig. 1. Results from a literature survey on the number of global change factors included in soil ecology experiments, covering the years 1957 to 2017.

Fig. 1

A. Frequency distribution of the number of factors of global change included in experimental studies. For the 19 studies testing 3-way interactions, we counted overall 38 investigated responses (across studies and variables), and in 21.05% of these authors reported a significant interaction. We found 5 studies including 4-way interactions, and in none of these was the 4-way interaction term significant. B. Number of experimental studies including a given number of factors over the last 50 years. For comparison, the dashed grey line (right y-axis) represents the number of published articles per year for the Web of Knowledge category “Ecology”. C. Number of papers including a given global change factor, for studies with 1-4 combined factors. D. Network graph depicting co-occurrence of global change factors in experimental studies, where circle size represents the frequency with which the driver was included in the studies and line thickness represents the frequency with which the drivers were tested as combinations.