Search for: All records

Primary forests play a crucial role in providing essential ecosystem services and supporting biodiversity compared to secondary forests. With increasing threats from extreme climate events and human activities, monitoring primary forest loss is critical for understanding the impact of these threats on ecosystems and biodiversity. Dense time series data from remotely sensed satellite imagery allow us to track historical disturbances, making it an effective source for mapping primary forests over time. However, distinguishing between primary and secondary forests based on spectral-temporal information remains challenging as primary forests can show high resilience to certain natural disturbances (e.g., drought), and secondary forests may not have experienced any disturbance during the satellite observation period. In this context, this study aims to map primary forests on the Caribbean island of Hispaniola using the time series approach and resilience metrics given that primary forests tend to be more resilient than secondary forests. To achieve this, we used spectral-temporal features from COntinuous monitoring of Land Disturbance (COLD) algorithm based on all available Landsat data between 1984 and 2023. Additionally, a resilience map is generated from deseasonalized and detrended spectral observations using the lag-1 autocorrelation method. Then, a Random Forest model was employed to generate an annual primary forest map. 

Primary forest (PF) is critical in supporting biodiversity and mitigating greenhouse gas emissions. However, the continuous monitoring of PF loss through remote sensing time-series observations remains largely unexplored, particularly in undeveloped and developing countries. In this study, we use the COntinuous monitoring of Land Disturbance (COLD) algorithm and Landsat time-series data to quantify PF loss on the island of Hispaniola, including Haiti and the Dominican Republic, from 1996 to 2022. The major findings include: (1) Haiti experienced a more pronounced PF loss compared to the Dominican Republic despite its lower PF coverage. From 1996 to 2022, PF in Haiti decreased from 0.64% to 0.35%, while PF in Dominican Republic decreased from 7.17% to 4.89%. (2) PF loss is observed both inside and outside protected areas. In Haiti, more PF loss occurs within protected areas than outside those areas. In the Dominican Republic, PF loss rates inside and outside protected areas are comparable. (3) The mean topographic slope of PF shows an increasing trend through time in both Haiti and Dominican Republic, suggesting slope plays a key role in PF loss. Despite the disparities between Haiti and Dominican Republic in preserving PF, urgent conservation policies are needed for the whole island. The land cover maps framework can be extended beyond the island of Hispaniola to larger regions for evaluating the impacts of PF loss on biodiversity conservation and ecosystem services.