Identification of Ecological Corridors for Semi-Aquatic Vertebrates: A Case of the Eurasian Otter in Northeast China.

As an indicator and flagship species of freshwater ecosystems, the Eurasian otter (Lutra lutra) plays a significant role in maintaining the connectivity and stability of ecosystems. However, compared with terrestrial and marine ecosystems, the conservation of freshwater ecosystems and species has not been sufficiently emphasized. In particular, research on the habitats and ecological corridors of semi-aquatic vertebrates remains inadequate. This study employed species distribution models and corridor construction models to predict the distribution range of suitable habitats and identify the ecological corridors and key points for the Eurasian otter in Northeast China. The results showed that our models demonstrated good performance in species distribution model evaluation/validation, with average True Skill Statistic (TSS) and Area Under the Curve (AUC) values of 0.934 and 0.995 respectively. The model predicted that the suitable habitats of the Eurasian otter were mainly distributed along the rivers in the forested mountainous areas including the Daxing'anling Mountains, the Xiaoxing'anling Mountains, and the Changbai Mountains. Moreover, there were 39 core habitats, 42 ecological corridors, 78 pinch points and 19 barrier points identified. Among these, 11.92% of the suitable habitats, 25.83% of the core habitats and 18.66% of the ecological corridors were included in the scope of protected areas, but there were still protection gaps. In the future, anthropogenic disturbances in the Northeast China Forest Belt should be strictly controlled, and the integrated protection of forest and freshwater ecosystems should be strengthened so as to improve ecosystem and species connectivity.