Does protected area connectivity moderate the efficacy of protection on tropical biodiversity? Evidence from a replication of Brodie et al. 2023

Abstract

To combat biodiversity loss, the United Nations has adopted the Kunming-Montreal Global Biodiversity Framework, which includes a 30x30 goal that calls for 30 percent of terrestrial, inland water, and coastal marine areas to be in well-connected and ecologically representative protected areas (PAs) by 2030. To justify this goal, PAs must be demonstrated to be an effective way to enhance biodiversity. Recent research by Brodie et al. (2023) suggests that PAs do in fact effectively preserve vertebrate biodiversity within their boundaries and in the adjacent unprotected landscape. However, the 30x30 goal, and the ecological literature that supports it, also suggest that the effect of PAs on biodiversity may be moderated by the connectivity of the surrounding PA network. PA Connectivity likely influences species movement, gene flow, and energy transfer, which in turn effect biodiversity. While Brodie et al. provide evidence of the efficacy of PAs, they do not assess whether the effect they observe is altered by network connectivity. If present, moderation has important implications for the 30x30 goal. If the efficacy of protection is amplified by connectivity, future PAs should be placed to maximize this biodiversity enhancing effect, given related objectives and constraints. To test for the influence of connectivity, we replicate the analysis of Brodie et al. and introduce PA connectivity as a statistical moderator of the effect PA status has on biodiversity. In the process, we directly replicate (reproduce) the original analysis and assess its conclusion validity. Our data, code, and reports are accessible in a Github repository.