Short-term spatial dynamics of neotropical otter ( Lontra longicaudis annectens ) during hydroelectric dam construction in southern Mexico

This study documented short-term spatial patterns of the neotropical river otter (Lontra longicaudis annectens) during hydroelectric dam construction in the Grijalva River, Chiapas, Mexico. Weekly systematic surveys were conducted in two zones during 2023-2024 (104 surveys per zone): a construction-Disturbed Zone and a less altered Riparian Zone. Methodological constraints-including absence of preconstruction baselines and a disturbance-gradient rather than control-impact design-limit causal inferences; findings represent preliminary observations temporally correlated with construction activities. Habitat use indices were higher in the Disturbed Zone (0.76 records/km) than the Riparian Zone (0.54 records/km). However, spatial analyses (Kernel density, Getis-Ord Gi*, Ripley's K function) revealed a 2.14 km southeast shift in activity hotspots toward the Riparian Zone during 2024, consistent with potential displacement patterns as construction intensified. Results provide preliminary insights for hydroelectric project management, emphasizing the need for robust preconstruction baseline monitoring and connected riparian corridors to facilitate species movement.