Extended Data Fig. 9: When analyzing only species with populations both inside and outside of protected areas (PAs), population trends remain higher overall in protected areas, again with the most prominent benefits for amphibians and birds (n = 1,356 time series).

Data were subset to 373 species for which population time series were available both inside and outside of PAs. Results from this narrower dataset are qualitatively consistent with those of the larger dataset of 1,032 species. We evaluated (a) the overall effect of protected areas on vertebrate trends and (b) whether all terrestrial vertebrate classes benefit equally from PAs. We used multilevel models wherein we controlled for variables used in pre-analysis matching in addition to governance, regional rates of climate change, and land cover change. To evaluate whether all vertebrate lineages benefit equally from PAs (b), we modeled the interactive effect of class and PA on population trends. Points represent mean estimates from a multilevel model and error bars represent 80% (wide) and 95% (narrow) Bayesian credible intervals (BCI). Asterisks indicate statistical support for effects and contrasts – 95% BCIs exclude zero. In panel b, small symbols represent individual population trends, and transparent symbols are estimates that are indistinguishable from zero.