Mangrove Disturbance and Recovery Following Hurricanes Irma and Maria (2017) in Florida and Puerto Rico

Two U.S. National Estuarine Research Reserves (NERRs), Rookery Bay (Florida) and Jobos Bay (Puerto Rico), experienced hurricanes in September 2017 (Irma and Maria) and 2022 (Ian and Fiona). We quantified mangrove canopy disturbance and recovery using pixel-wise annual land-cover trajectories from 2 m WorldView™ imagery (2017–2024) and monthly Sentinel-2 and Landsat Normalized Difference Vegetation Index (NDVI) time series (2016–2025). Mangrove target areas (MTAs) comprised pixels classified as mangrove in the pre-storm 2017 map and consistent coverage across the subsequent available maps. In 2018, mapped mangrove cover declined to 47% in the southeastern Rookery Bay MTA (sRB-MTA) and 59% in the Jobos Bay MTA (JB-MTA), with most disturbed pixels reclassified as soil. Intermediate mapped classes represented spectral and surface-condition changes rather than discrete ecological states. Despite greater initial loss, mapped mangrove cover reached 90% in the sRB-MTA by 2023, compared with 79% in the JB-MTA in 2023 and 83% in 2024. Recovery was spatially heterogeneous: pixels initially reclassified as mixed low-relief vegetation showed higher recovery percentages by 2023 (sRB-MTA: 92%; JB-MTA: 81%) than those reclassified as coastal water (48% and 23%, respectively). Persistent non-recovery of mangrove class coincided with pre-existing hydrologic stressors in both regions, and unauthorized coastal development in Jobos Bay NERR. Areas that subsequently returned to the mangrove class showed a sharp post-storm NDVI decline, followed by an initial rapid rebound and gradual recovery toward climatological greenness and seasonality by mid-2022. NDVI recovery began earlier in Jobos Bay (November 2017) than in southern Rookery Bay (June 2018). No widespread canopy response was detected following the 2022 storms, consistent with weaker local wind exposure but not excluding other ecological effects. Together, land-cover trajectories and the NDVI resolved complementary canopy recovery patterns without establishing restoration of pre-storm forest structure or ecosystem function.