sUAS-Based High-Resolution Mapping for the Habitat Quality Assessment of the Endangered Hoolock tianxing Gibbon

The endangered Gaoligong hoolock gibbon (Hoolock tianxing) faces significant threats from habitat degradation and loss, making accurate habitat assessment crucial for effective conservation. This study explored the effectiveness of high-resolution small unoccupied aerial system (sUAS) imagery for evaluating habitat quality, comparing its performance against Sentinel-2 satellite data. Focusing on the critically fragmented habitat of this primate in Yingjiang County, China, we aimed to (1) assess habitat quality at the patch level using a sUAS; (2) apply the InVEST Habitat Quality (IHQ) model; and (3) compare the effectiveness of sUAS and Sentinel-2 imagery, across different resolutions, for habitat quality evaluation. We utilized sUAS imagery (0.05 m resolution) obtained from a DJI Mavic 3 drone and Sentinel-2 data (10 m resolution) for a comparative analysis. The InVEST IHQ model was then used to analyze nine habitat patches, examining how data resolution impacts habitat quality assessments. Our results showed that habitat quality varied considerably across space, with lower quality observed near villages due to agricultural activity and infrastructure development. The sUAS imagery proved superior at capturing detailed landscape features and delineating small, fragmented patches compared to Sentinel-2. Furthermore, the sUAS achieved higher classification accuracy. Although both data sources indicated generally high habitat quality, Sentinel-2 tended to overestimate both habitat quality and degradation compared to the sUAS. High-resolution sUAS imagery therefore provides a clear advantage for detailed habitat quality assessment and targeted conservation planning, especially in fragmented landscapes. Integrating sUAS data with other remote sensing methods is essential to improve the protection of endangered primate habitats. This research emphasizes the value of sUAS for fine-scale habitat analysis, providing a strong scientific basis for developing targeted habitat restoration strategies and guiding conservation management.