Can protected areas safeguard forests on small islands? Evidence from Trinidad

Protected natural areas (PNAs) are central to the Global Biodiversity Framework (GBF), as is measuring their effectiveness. On Small Island Developing States (SIDS), PNA designation and management is socio-politically challenging, due to pressure from conflicting interests and complex land-use histories on limited land areas. Global and regional-scale analyses of PNA effectiveness lack the spatial resolution to gain critical planning and management insights for SIDS and island-level evidence is limited to a handful of studies for terrestrial systems. Forest extent is a valuable tool for monitoring management interventions. For a Caribbean SIDS, we examined forest loss and fragmentation in PNAs between 2000 and 2022 as a proxy for PNA effectiveness, using Propensity Score Matching and Generalised Linear Mixed Modelling. Using the Global Forest Change remote sensing dataset, island-wide forest cover on Trinidad was estimated at 52% in 2000, of which 42% was located in PNAs. Proximity to roads and forest plantations and lack of designation as a PNA were significantly correlated with forest loss. Although forest loss was significantly lower within PNAs than comparable sites outside PNAs, 73% of PNAS experienced increased fragmentation during the study period. Increases in PNA fragmentation were most strongly associated with initial forest cover, human population density and elevation. Forest loss was lower in PNAs with higher levels of designation, suggesting some benefit of limiting anthropogenic activities. However, the continued degradation of PNAs highlights the need for proactive management to avoid PNAs becoming paper parks. This assessment presents an opportunity to prioritise areas to implement nature-based solutions and enable accurate natural capital accounting. Our analysis of terrestrial protected areas on an ecologically important Caribbean SIDS provides insights for indicators of progress towards GBF targets and emphasises the value of spatial planning on islands that explicitly considers the landscape-scale impact of competing economic interests.