Figure 1. Number of reviews, comparative analyses and meta-analyses referenced on the Web of Science in ecology, evolution and conservation between 1995 and 2012 in birds, mammals and herptiles (amphibians and reptiles).

The three slopes are significantly different from 0 (p<0.006 in the 3 cases), and the increase in the number of review papers across time is significantly smaller in amphibians and reptiles than it is in birds (p = 0.009) or mammals (p<0.001), but does not significantly differ between birds and mammals (p = 0.332).