If a tree is “Protected”, is it? Using satellite-borne LiDAR to understand efficacy of protection status in West and Central African Protected Areas

Globally, Protected Areas (PAs) have had positive impacts on habitat protection and carbon storage and are viewed as critical for preserving hotspots of biodiversity and supporting SDG 15: Life on Land. However, global studies indicate that Afrotropical PAs may be more degraded and less effective than PAs in other regions, despite comparable geographic coverage. Here, we match PAs to Non-Protected Counterfactuals (NPCs) to understand how PA presence in West and Central Africa affects forest structure and structural diversity. Using the Global Ecosystem Dynamics Investigation (GEDI), we demonstrate that PAs have an inconsistent effect on canopy height, structural diversity, and plant area index across the region, varying by both country and PA designation. We found PA impact on preserving ecological structure may have a positive relationship with background deforestation rates, where positive differences between PAs and NPCs were particularly prominent in countries experiencing high deforestation. This highlights the need to take country-wide deforestation rates and socioeconomic pressures into account when understanding PA efficacy, as the lack of difference between PAs and NPCs in low deforestation countries does not necessarily indicate inadequate conservation outcomes. Our results demonstrate that governance type and PA establishment goals affect ecological outcomes, with forest structure consistently higher in National Parks. Our study reveals that when deforestation and country-wide values of structural metrics are factored into PA assessments, PAs in Africa have a higher positive impact than previously identified. Therefore, when assessing PAs effectiveness in regions like West and Central Africa, consideration of country-wide and designation-specific dynamics go beyond global studies to describe PA impact and outcomes.