Figure 1.
Map of the study sites by the centroid coordinates of protected areas for inside-outside pairwise comparisons (black dots; n = 71) and inside only comparisons (red dots; n = 32).
Both categories include data where studies reported across clusters of protected areas.
Figure 2.
Effect sizes and 95% confidence intervals of response variables (A), taxa (B), continent (C) and the Protected Areas IUCN category (D).
Positive boxplot values indicate a net positive impact of protected areas (PAs) on biodiversity. Sample sizes are in grey, the vertical black lines show a zero effect size, while the dashed lines show the overall effect size of 0.444. The effect size for the truncated bar (Europe; Panel C) with large variance due to low sample sizes is 2.54 CI: 0.36–4.73. Abund = Abundance; Spp. Rich. = Species richness; AF = Africa; AS = Asia; SA = South America; NAM = North America; AU = Australasia; EU = Europe. IUCN categories are detailed in Appendix S2.
Table 1.
Effect sizes (ES), lower bound (lbCI) and upper bound (ubCI) confidence intervals and sample sizes (N), Tau square (I2), Q statistic (Q) with its p-value (Qp) for at different subgroup designations.
Figure 3.
Effect sizes and 95% confidence intervals for species abundance responses by their IUCN Red List status.
Positive boxplot values indicate a net positive impact of protected areas on species abundance. Note that multiple responses may be reported for one species (unique species = 168, total cases = 251) and taxonomic uncertainties, Not Evaluated and Data Deficient species are excluded (n = 79). The vertical black line shows a zero effect size while the dashed line indicates the overall effect size for species abundance responses (0.517). Taxa included mammals, birds, herptiles and plants.